U.S. patent number 7,220,228 [Application Number 09/900,503] was granted by the patent office on 2007-05-22 for surgical retractor blade and system.
This patent grant is currently assigned to Cardiothoracic System, Inc.. Invention is credited to Harry L. Green, II, Lawrence W. Hu, David J. Paul, Eugene E. Reis.
United States Patent |
7,220,228 |
Hu , et al. |
May 22, 2007 |
**Please see images for:
( Certificate of Correction ) ** |
Surgical retractor blade and system
Abstract
In accordance with the present invention, there is disclosed
surgical methods and apparatus for accessing and stabilizing the
heart. The methods and apparatus facilitate access to an
anastomosis site, allows various instruments or devices to be
maneuvered and secured in place, and provide stabilization of the
heart. In particular, the apparatus involves a retractor apparatus
having one or more opposing blades having a channel adapted to
engage an incision in a patient. The retractor blades may have
features to cooperatively engage an instrument mount. The
instrument mount preferably is configured to hold an instrument,
such as a tissue stabilizer, and allows the instrument to be easily
maneuvered. The retractor blades may have a number of suture locks
for securing sutures used during surgery. The retractor system is
particularly useful in accessing, positioning and stabilizing the
beating heart for coronary artery bypass graft surgery.
Inventors: |
Hu; Lawrence W. (Mountain View,
CA), Paul; David J. (Scotts Valley, CA), Reis; Eugene
E. (San Jose, CA), Green, II; Harry L. (Santa Cruz,
CA) |
Assignee: |
Cardiothoracic System, Inc.
(Santa Clara, CA)
|
Family
ID: |
23182454 |
Appl.
No.: |
09/900,503 |
Filed: |
July 6, 2001 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20020004628 A1 |
Jan 10, 2002 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09305811 |
May 4, 1999 |
6283912 |
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Current U.S.
Class: |
600/210;
600/232 |
Current CPC
Class: |
A61B
17/02 (20130101); A61B 17/0206 (20130101); A61B
17/0483 (20130101); A61B 90/57 (20160201); A61B
2017/0243 (20130101); A61B 90/50 (20160201) |
Current International
Class: |
A61B
1/32 (20060101) |
Field of
Search: |
;600/206,210,213,227,231,232,235,233 |
References Cited
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|
Primary Examiner: Gart; Matthew S
Attorney, Agent or Firm: Law Office of Alan W. Cannon
Parent Case Text
This application is a continuation of application Ser. No.
09/305,811, filed May 4, 1999 now issued as U.S. Pat. No.
6,282,912.
Claims
What is claimed is:
1. A surgical retractor blade for attaching to a drive mechanism,
said retractor blade comprising a body having a first end, a second
end, a channel adapted to engage one side of an incision in a
patient, said first end having a first cavity adapted to receive a
support member extending from said drive mechanism and a second
cavity adapted to receive a second support member extending from
said drive mechanism.
2. The surgical retractor blade of claim 1 wherein said channel is
adapted to receive an incised sternum.
3. The surgical retractor blade of claim 1 wherein said first
cavity is a blind hole having a predetermined depth from said first
end.
4. The surgical retractor blade of claim 3 wherein said blind hole
is substantially cylindrical.
5. The surgical retractor blade of claim 3 wherein said depth is at
least about 1.125 inches long.
6. The surgical retractor blade of claim 1 wherein said first
cavity becomes progressively smaller in a direction away from said
first end.
7. A detachable surgical retractor blade for attaching to a drive
mechanism, said retractor blade comprising a body having a first
end, a second end, a channel adapted to engage one side of an
incision in a patient, and a rail extending along at least a
portion of said body, wherein said rail has a top portion and a
bottom portion, said bottom portion having a narrowed region
adjacent said top portion forming first and second tabs on said top
portion; and wherein said retractor blade is detachable from the
drive mechanism even when said retractor blade is applying force
through said channel to one side of the incision.
8. A surgical retractor blade, said retractor blade comprising a
body having a fist end adapted to attached to a separate, complete
driving mechanism, a second end, a channel adapted to engage one
side of an incision in a patient, a rail extending along at least a
portion of said body, and a plurality of open slots for receiving a
suture therein, wherein said open slots have a internal wall and a
suture locking member having a fixed end a free end, engaging said
internal wall so as to clamp a suture placed between said free end
and said internal wall.
9. The surgical retractor blade of claim 8, wherein said suture
locking member is substantially rigid and pivots about said fixed
end.
10. The surgical retractor blade of claim 9, further comprising a
spring member based against said suture locking member to forcibly
urge said free end towards said internal wall.
11. A surgical retractor blade for attaching to a drive mechanism,
said reactor blade comprising a body having a first end, a second
end, a channel adapted to engage one side of an incision in a
patient, a rail extending along at least a portion of said body,
and a plurality of open slots for receiving a suture therein,
wherein at least one of said open slots have a first slots section
which bifurcates into a second slot section and a third slots
section.
12. The surgical retractor blade of claim 11 wherein each of said
second and third slot sections have an internal wall and a suture
locking member having a fixed end and a free end, said free end
engaging said internal wall so as to clamp a suture placed between
said free end and said internal wall.
13. A surgical retractor blade for attaching to a drive mechanism,
said retractor blade comprising a body having a first end, a second
end, a channel adapted to engage one side of an incision in a
patient, and a rail extending along at least a portion of said
body, wherein said first end has a cavity adapted to receive a
support member extending from said drive mechanism.
14. The surgical retractor blade of claim 13 wherein said cavity is
a tapered hole.
15. The surgical retractor blade of claim 14 further comprising a
flexible polymeric flap adapted to flexibly engage soft tissue
surrounding said incision.
16. The surgical retractor blade of claim 1, wherein said body
comprises a polymer.
17. The surgical retractor blade of claim 7, wherein said body
comprises a polymer.
18. The surgical retractor blade of claim 8, wherein said body
comprises a polymer.
19. The surgical retractor blade of claim 11, wherein said body
comprises a polymer.
20. The surgical retractor blade of claim 13, wherein said body
comprises a polymer.
21. A surgical retractor blade for attaching to a drive mechanism,
said retractor blade comprising a body having a first end, a second
end, a channel adapted to engage one side of an incision in a
patient, a rail extending along at least a portion of said body,
and a plurality of open slots for receiving a suture therein,
wherein said open slots have an internal wall and a suture locking
member having a fixed end and a free end, said free end engaging
said internal wall so as to clamp a suture placed between said free
end and said internal wall, wherein said suture locking member is
substantially rigid and pivots about said fixed end.
22. The surgical retractor blade of claim 21, further comprising a
spring member biased against said suture locking member to forcibly
urge said free end towards said internal wall.
23. A surgical retractor blade, said retractor blade comprising a
body having a fist end adapted to attached to a separate, complete
driving mechanism, and a second end, wherein said first end
comprises a first opening extending into body, said first opening
extending from said first end into said body, said second opening
configured for receiving a second extension from the retractor
driving mechanism.
24. The surgical retractor blade of claim 23, further comprising a
locking mechanism to lock said blade to said retractor mechanism
when in a locked orientation, and to unlock said blade from said
retractor mechanism when in an unlocked orientation.
25. The surgical retractor blade of claim 23, wherein said first
opening is tapered to become progressively smaller in direction
away from said first end.
26. The surgical retractor blade of claim 24, wherein said
extension that said first opening is configured for receiving
includes a notch, and wherein said locking mechanism comprises a
latch member for engaging the notch.
27. The surgical retractor blade of claim 23, wherein said second
opening is tapered to become progressively smaller in direction
away from said first end.
28. The surgical retractor blade of claim 23, further comprising a
rail extending along at least a portion of said retractor
blade.
29. The surgical retractor blade of claim 28, wherein said rail
comprises a top portion, and a bottom portion having a narrowed
region adjacent said top portion, forming first and second tabs on
said top portion.
30. The surgical retractor blade of claim 28, wherein said rail is
curved along its length.
31. The surgical retractor blade of claim 23, further comprising a
plurality of open slots for receiving and securing a suture
therein.
32. The surgical retractor blade of claim 28, further comprising a
plurality of open slots formed in said rail for receiving and
securing a suture therein.
33. The surgical retractor blade of claim 23, further comprising a
flexible flaps adapted to flexibly engage soft tissue surrounding
the incision.
34. The surgical retractor blade of claim 23, wherein said body
comprises polymeric material.
35. A surgical retractor blade, said retractor blade comprising a
body having a fist end, second end, a channel adapted to engage one
side of an incision in a patient, a rail extending along at least a
portion of said elongated body, and a plurality of open slots
formed in said rail for receiving a suture therein, wherein said
first end is adapted to be releasably attached to a retractor drive
mechanism.
36. The surgical retractor blade of claim 35, wherein at least one
of said open slots comprises a first slot section which bifurcates
into a second slot section and a third slot section.
37. The surgical retractor blade of claim 36, wherein each of said
second and third slots sections have a internal wall and a suture
locking member having a fixed end and a free end, said free end
engaging said internal wall so as to clamp a suture placed in
between said free end and said internal wall.
38. A surgical retractor system for creating an opening through an
incision in a patient, said system comprising: a driving mechanism
having a main body and first and second extensions extending from
said main body, said first extension being movable relative to said
second extension; and first and second retractor blades releasably
attached to said first and second extension, respectively, wherein
said first and second blades, when attached, are incapable of
rotational displacement with respect to said first and second
extensions; wherein each of said first and second retractor blades
comprises a elongated body having a first end and a second end,
said first end having an opening to receive a respective one of
said first and second extensions, wherein each said opening is
close ended at an end nearest said second end of said retractor
blade in which said in which said opening is formed,
respectively.
39. The surgical retractor system of claim 38, wherein at least one
of said first and second retractor blades including a plurality of
open slots for receiving a suture therein.
Description
FIELD OF THE INVENTION
The present invention relates generally to surgical instruments,
and more particularly to surgical retractor, instrument mount, and
tissue stabilizer devices for use during coronary artery bypass
graft surgery.
BACKGROUND OF THE INVENTION
Diseases of the cardiovascular system affect millions of people
each year and are a leading cause of death throughout the world.
The cost to society from such diseases is enormous both in terms of
the number of lives lost as well as in terms of the costs
associated with treating patients through traditional surgical
techniques. A particularly prevalent form of cardiovascular disease
is a reduction in the blood supply leading to the heart caused by
atherosclerosis or other condition that creates a restriction in
blood flow at a critical point in the cardiovascular system that
supplies blood to the heart.
Treatment of such a blockage or restriction in the blood flow
leading to the heart is, in many cases, treated by a surgical
procedure known as a coronary artery bypass graft (CABG) procedure,
more commonly known as a "heart bypass" operation. In the CABG
procedure, the surgeon "bypasses" the obstruction to restore normal
blood flow to the heart either by attaching an available source
vessel to the obstructed target coronary artery or by removing a
portion of a vein or artery from another part of the body, to use
as a graft, and installing the graft between a point on a source
vessel and a point on a target artery.
To restore the flow of blood to the heart, the CABG procedure
requires that a fluid connection be established between two
vessels. This procedure is known as an "anastomosis." Typically, a
source vessel, such as a source artery with an unobstructed blood
flow, i.e., the left internal mammary artery (LIMA), or a
bypass-graft having one end sewn to an unobstructed blood source
such as the aorta, is sewn to a target occluded coronary artery,
such as the left anterior descending (LAD) artery or other vessel,
that provides blood flow to the muscles of the heart.
Although the CABG procedure has become relatively common, the
procedure itself is lengthy and traumatic and can damage the heart,
the cardiovascular system, the central nervous system, and the
blood supply itself. In a conventional CABG procedure, the surgeon
makes an incision down the center of the chest, cuts through the
sternum, performs several other procedures necessary to attach the
patient to a heart-lung bypass machine, cuts off the blood flow to
the heart, and then stops the heart from beating in order to
complete the bypass. The most lengthy and traumatic surgical
procedures are necessary, in part, to connect the patient to a
cardiopulmonary bypass (CPB) machine to continue the circulation of
oxygenated blood to the rest of the body while the bypass is
completed.
In recent years, a growing number of surgeons have begun performing
CABG procedures using surgical techniques especially developed so
that the CABG procedure could be performed while the heart is still
beating. In such procedures, there is no need for any form of
cardiopulmonary bypass, no need to perform the extensive surgical
procedures necessary to connect the patient to a cardiopulmonary
bypass machine, and no need to stop the heart. As a result, these
beating heart procedures are much less invasive and the entire
procedure can typically be achieved through a small number,
typically one or two, comparatively small incisions in the
chest.
Despite the advantages, the beating-heart CABG procedure is not
universally practiced, at least in part, because of the difficulty
in performing the necessary surgical procedures using conventional
surgical instruments. For example, it has been difficult for the
surgeon to access the required areas of the heart requiring
revascularization. In addition, the various surgical steps that are
required to be performed on the heart itself are more difficult to
perform because the heart muscle continues to move and contract to
pump blood throughout the duration of the procedure.
The specific portion of the surgical procedure that creates the
anastomosis in the beating-heart CABG procedure is particularly
difficult. Completion of the anastomosis requires placing a series
of sutures through extremely small vessels on the surface of the
heart while the heart muscle continues to beat. Moreover, the
sutures must be carefully placed to ensure that the source vessel
or graft is firmly attached and will not leak when blood flow
through the vessel is established. In cases where the target
coronary artery is temporarily obstructed, for example, to improve
the surgeon's visibility and avoid excessive blood loss, it is also
important that the anastomosis procedure be performed rapidly to
avoid ischemic damage to the heart.
Further adding to the difficulty of the procedure is the fact that
the working space and visual access are often quite limited. The
surgeon may be working through a small incision in the chest, for
example, or may be viewing the procedure on a video monitor if the
site of the surgery is viewed via surgical scope. The vessel, and
particularly the arteriotomy to which a source vessel is to be
anastomosed, may also be very difficult for the surgeon to see as
it may be obscured more or less by layers of fat or other
tissue.
The beating-heart CABG procedure could be greatly improved if the
heart could be accessed and stabilized during the procedure such
that the motion of the heart, particularly at the site of the
anastomosis, is minimized even though the heart continues to beat
and supply blood to the body. The beating-heart CABG procedure
could be further improved if the target vessel, and specifically
the arteriotomy was presented to the surgeon in a way that allows
sutures to be easily placed.
In view of the foregoing, it would be desirable to have improved
devices for accessing and effectively stabilizing the beating heart
at the site of the anastomosis. It would be desirable to have a
retractor system that provides unobstructed and organized access to
the areas of the heart requiring revascularization. It would be
further desirable to have a low-profile, atraumatic stabilizing
device that stabilizes the beating heart at the site of the
anastomosis and provides a favorable presentation of the target
vessel and the arteriotomy. It would be further desirable to
provide a mount for the stabilizing device, or other instruments,
that allows the stabilizing device to be easily maneuvered to the
desired position and orientation, fixedly secured until the
procedure is completed, and then easily removed from the site of
the anastomosis.
SUMMARY OF THE INVENTION
The present invention will be described for use in performing CABG
surgery, but the invention is not limited thereto, and is
contemplated to be useful for other surgical procedures requiring
access through an incision into a patient.
The present invention involves various aspects of a surgical
retractor for use, for example, in performing a CABG procedure on a
beating heart. The present invention may involve a surgical
retractor platform blade which facilitates the creation of a
working opening through an incision in a patient, such as a
sternotomy, and may also provide a platform for securely mounting
various instruments or for organizing such things as sutures. The
present invention may also include an instrument mount which may be
secured to the platform.
One aspect of the present invention involves a surgical retractor
blade for attaching to a drive mechanism for use in spreading apart
opposite sides of an access incision in a patient. The retractor
blade may have a unitary body which includes a first end, a second
end, and a channel adapted to engage one side of an incision in
patient, preferably an incised sternum. The body is preferably
polymeric, but may be metal, a composite material, or other
suitable substantially rigid, load bearing material. The first end
preferably has a cavity adapted to receive a support member
extending from said drive mechanism. In one embodiment, the first
cavity is a blind hole having a predetermined depth from the first
end. Preferably, the depth is at least about 1.125 inches. The
cavity may be tapered, becoming progressively smaller in a
direction away from the first end. The retractor blade may have a
second cavity adapted to receive a second support member extending
from the drive mechanism.
Another aspect of the present invention involves a surgical
retractor blade having a polymeric body having a channel adapted to
engage one side of an incision in a patient and a rail extending
along at least a portion of the polymeric body. The surgical
retractor blade is preferably removably attachable to a drive
mechanism. Preferably, the rail has a top portion and bottom
portion, the bottom portion having a narrowed region adjacent the
top portion thus forming first and second tabs on said top portion.
Preferably the rail is curved along its length. The surgical
retractor blade may have a cavity, preferably in the form of a
tapered hole, adapted to receive a support member extending from a
drive mechanism.
The surgical retractor may further include a plurality of open
slots for receiving a suture therein. The open slots preferably
have an internal wall and a suture locking member having a fixed
end and a free end, the free end engaging the internal wall so as
to clamp a suture placed between the free end and the internal
wall. Preferably, the suture locking member is substantially rigid
and pivots about its fixed end. The invention may also include a
spring member biased against the suture locking member to forcibly
urge the free end towards the internal wall.
In one embodiment of the retractor blade, at least one of the open
slots has a first slot section which bifurcates into a second slot
section and a third slot section. Preferably, each of the second
and third slot sections has an internal wall and a suture locking
member having a fixed end and a free end, the free end engaging the
internal wall so as to clamp a suture placed between the free end
and the internal wall.
In a preferred embodiment, the retractor blade may include a soft
tissue retainer for covering or retaining the soft tissue
surrounding the incision site. In a preferred embodiment, the soft
tissue retainer may be a flexible polymeric flap extending from the
body of the retractor blade. The polymeric flap is adapted to
flexibly engage and soft tissue and fat to keep them away from the
platform area of the retractor body. The flexible polymeric flap is
preferably injection molded over a portion of the retractor blade
body.
These and other features of the present invention will become more
fully apparent from the following description and appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating a cardiac surgery system
according to the principles of the present invention.
FIG. 2 is a perspective view illustrating a retractor assembly
according to the principles of the present invention.
FIG. 3 is a perspective view illustrating a preferred retractor
drive assembly.
FIG. 4 is a perspective view illustrating an exemplar bar
assembly.
FIG. 5 is a perspective view illustrating a moveable housing
associated with the retractor drive.
FIG. 6 is a perspective view illustrating a retractor drive handle
assembly.
FIG. 7 is a top plan view illustrating a preferred platform blade
and retractor drive assembly in an unengaged position.
FIG. 8 is a top view in partial cross-section illustrating the
platform blade and retractor drive assembly in an engaged
position.
FIG. 9 is a cross-sectional view taken along line 9--9 shown in
FIG. 8.
FIG. 10 is a partial top view illustrating a preferred suture stay
arrangement associated with a platform blade.
FIGS. 11A, 11B, and 11C illustrate a preferred platform blade
latch.
FIGS. 11A and 11B are top and front plan view, respectively.
FIG. 11C is a cross-sectional view taken along line 11C--11C as
shown in FIG. 11B.
FIG. 12 is a perspective view showing a preferred suture lock.
FIG. 13 is a perspective view illustrating an instrument mount
assembly according to the principles of the present invention.
FIG. 14 is an exploded assembly illustration of the instrument
mount assembly of FIG. 13.
FIGS. 15A and 15B are perspective views illustrating the assembly
of the mount cam to the mount base.
FIGS. 16A and 16B are top and front plan views, respectively,
illustrating a preferred mount cam.
FIG. 17 is a front plan view illustrating a preferred mount
hinge.
FIG. 18 is an exploded view illustrating the assembly of the mount
body to the mount base.
FIG. 19 is an exploded view illustrating the assembly of the
instrument clamp to the mount body.
FIG. 20 is a cross-sectional view taken through a horizontal plane
of the instrument shaft grip of FIG. 19.
FIG. 21 is a front plan view showing an assembled instrument mount
operably positioned on a platform blade according to the principles
of the present invention.
FIGS. 22A and 22B are front and top plan views, respectively, of an
alternate instrument mount assembly according to the principles of
the present invention.
FIG. 23 is a cross-sectional view taken along line 23--23 as shown
in FIG. 21.
FIG. 24 is an offset cross-sectional view taken along line 24--24
as shown in
FIG. 22 illustrating the mount assembly of FIGS. 21 and 22 in the
closed position.
FIG. 25 is an offset cross-sectional view illustrating the mount
assembly of FIGS. 21 and 22 in the open position.
FIG. 26 is an exploded assembly view showing selected components of
a preferred closing mechanism.
FIG. 27 is a perspective view illustrating a preferred instrument
mount cam post.
FIG. 28 is a perspective view illustrating a preferred instrument
mount release button.
FIG. 29 is a perspective view illustrating a preferred instrument
mount follower post.
FIG. 30 is a perspective view of a preferred instrument mount shaft
clamp.
FIG. 31 is a perspective view of a preferred instrument mount
conical clutch.
FIG. 32 is a perspective view of a threaded collar associated with
the instrument mount shaft clamp.
FIGS. 33 and 34 are exploded perspective and cross-sectional views
respectively of a handle mechanism of a preferred tissue
stabilizer.
FIG. 35 is an exploded perspective view of a contact member of the
stabilizer shown in FIGS. 33 and 34.
FIG. 36 is a rear plan view of the contact member of FIGS. 33, 34
and 35.
FIG. 37 is a cross-sectional view of the contact member of FIG. 36
taken along line 37--37.
FIG. 38 is a perspective view illustrating a stabilizer base
embodiment having an offset shaft connection.
FIG. 39 is a perspective view illustrating an alternative offset
stabilizer base in use over a target vessel.
FIGS. 40A and 40B are respectively front and side plan views of the
offset stabilizer base embodiment of FIG. 39.
FIG. 41 is a perspective view of a tissue stabilizer having a
moveable ball/post.
FIG. 42 is a perspective view illustrating another tissue
stabilizer embodiment having a moveable ball/post.
FIG. 43 is a partial cross-section taken through the ball/post of
FIG. 42 showing a spring biased ball/post.
FIG. 44 is a partial cross-section showing the ball/post of FIG. 43
utilizing a locking clip to secure the ball/post.
FIG. 45 is a perspective view of the locking clip of FIG. 44.
FIG. 46 is a perspective view illustrating another moveable
ball/post stabilizer embodiment.
FIG. 47 is a front perspective exploded view of a stabilizer base
assembly having an adjustable ball/post position.
FIG. 48 is a rear perspective view of the stabilizer base of FIG.
47.
FIGS. 49A and 49B are front and rear perspective views of the
stabilizer base assembly of FIG. 47.
FIG. 50 is a partial cross-sectional view through a portion of the
rear guide slot of the stabilizer base of FIG. 47.
FIG. 51A is a perspective view of a stabilizer base embodiment
having a single contact member and bail construction.
FIG. 51B is an end plan view of the stabilizer embodiment of FIG.
51A.
FIGS. 52A and 52B are perspective views illustrating another
stabilizer base embodiment having a single contact member and bail
construction.
FIGS. 53 and 54 are perspective views illustrating stabilizer base
embodiments having a single contact member and a bail having a
mechanical drive.
FIG. 55 is a perspective view of a preferred cardiac surgery system
during operation according to the principles of the present
invention.
DETAILED DESCRIPTION
The present invention involves surgical instruments for accessing
and stabilizing the heart and methods for their use. The present
invention may involve a retractor system or assembly for accessing
the heart. The present invention may also include a mount that
allows various instruments to be easily positioned within the
surgical working space, locked or secured into a desired position
for the duration of a particular surgical procedure, and then
easily and safely removed from the working space. According to a
preferred embodiment the instrument may be a device to facilitate
stabilization of the heart during coronary surgery.
Although the instruments and methods of the present invention may
have application in both conventional stopped-heart and beating
heart procedures, they are preferably used to access and stabilize
the beating heart during a minimally invasive coronary artery
bypass graft (CABG) operation which has been specially developed to
facilitate completion of an anastomosis, typically between a target
artery and a bypass graft or source artery, without requiring
cardiac arrest such as cardioplegia or fibrillation and without
cardiopulmonary bypass (CPB). Further, although the instruments for
accessing and stabilizing the beating heart can be applied in a
number of different surgical contexts involving various incisions
and surgical approaches to the heart as are known in the art, the
instruments and devices described herein are most advantageously
employed in a CABG procedure wherein the heart is accessed through
only one or two minimally invasive incisions in the chest.
Although the particular source vessel and target artery of the
anastomosis are determined clinically, a common minimally invasive
bypass procedure on the beating heart includes an anastomosis which
forms a connection between the left internal mammary artery (LIMA)
as the source artery, and the left anterior descending artery (LAD)
as the target artery. To complete the anastomosis, the surgeon must
dissect a portion of the LIMA by separating it from the internal
chest cavity. Once dissection of the LIMA is achieved, the surgeon
may attach the dissected LIMA to the target coronary artery, i.e.,
the LAD by way of creating an anastomosis.
In this example, the present invention may involve a number of
discreet components that facilitate access to the anastomosis site,
allow various instruments or devices to be maneuvered and secured
in place, and provide stabilization of the heart. The retractor of
the present invention may be used to provide access to the
anastomosis site of the target artery on the heart itself. The
various stabilizer embodiments of the present invention may be used
to stabilize the beating heart during at least the portion of the
procedure during which the surgeon completes the anastomosis of the
LIMA to the LAD. The mount of the present invention may be used to
facilitate convenient manipulation of the stabilizer, and other
instruments or devices, to their desired position and allows the
devices to be secured in that desired position. Although the LIMA
to LAD anastomosis is provided as one example, it is readily
appreciated that the techniques and instruments described herein
may be applied to other procedures depending on the clinical
diagnosis and the patient's anatomy.
Although each component of the present invention may be used
separately with great benefit, the components are preferably used
in unison to provide a surgical system which provides an
unobstructed and organized surgical field, exceptional instrument
maneuverability and access to the heart facilitating total
revascularization of the heart if required, and effective vessel
stabilization during the anastomosis procedure. Although the
present invention will have application whether access to the heart
is achieved by way of a full-sternotomy, mini-sternotomy,
para-sternotomy, thoracotomy or other known approach, the exemplar
embodiments described below will be generally described with
reference to a coronary artery bypass procedure using a mid-sternal
approach.
Referring to the figures wherein like numerals indicate like
elements, an exemplar surgical system for performing a mid-sternal
surgical procedure on the beating heart is illustrated in FIG. 1
and includes retractor assembly 10, mount assembly 20 and
stabilizer assembly 30.
Retractor assembly 10 generally includes a pair of opposing blades
adapted to engage opposite sides of a sternal incision, or other
incision, and a drive mechanism constructed to force the blades,
and thus the sternum apart. Using the drive mechanism, the sternum
may be spread to the desired opening, thus providing the desired
access and direct visualization of the thoracic cavity. If desired,
the heart may be positioned or oriented to best present the target
vessels for anastomosis. This positioning may be established, for
example, through the strategic placement and tensioning of sutures
in the pericardial sac, by appropriately placing the patient in the
Trendelenburg position, or by using a heart positioner in the form
or a strap or pad or the like.
Once the target vessel is in the desired position, at least one
component of stabilizer assembly 30 is brought into contact with
the beating heart adjacent the target site of the anastomosis. The
surgeon then applies a stabilizing force to the beating heart via
the stabilizer assembly 30 which may then be fixed in place,
preferably to the retractor assembly 10 by way of mount assembly
20. The stabilizing force supplied by the stabilizer assembly
substantially eliminates movement of the heart in the area of the
anastomosis so that the surgeon may accurately and efficiently
perform the required anastomosis (or other surgical procedure).
After the anastomosis has been completed, the stabilizing force is
released and the contacting component of stabilizer assembly 30 is
removed from the anastomotic site.
Each of the principal components, the preferred surgical system,
and their methods of use are separately described in detail below.
A preferred retractor according to the principles of the present
invention is described below with reference to FIGS. 2 12. A
preferred stabilizer or instrument mount according to the
principles of the present invention is described below with
reference to FIGS. 13 32. Preferred stabilizer embodiments
according to the principles of the present invention are described
below with respect to FIGS. 33 44. A preferred surgical system and
methods for performing a coronary artery bypass on a beating heart
according to the principles of the present invention is described
below with respect to FIG. 45.
The Retractor
According to the principles of the present invention, the retractor
generally involves a drive mechanism and a pair of opposing blades
adapted for insertion into an incision and for engaging opposite
sides of the incision. The drive mechanism functions in some manner
to urge the opposing blades apart, thus forcing opposite sides of
the incision open to allow surgical access through the incision.
For purposes of performing a coronary artery bypass, the incision
may be any suitable incision which provides the desired access to
the thoracic cavity, and more specifically a desired area of the
heart. For purposes of example only, the retractor of the present
invention will be described with respect to a mid-sternal incision,
however skilled artisans will recognize that many aspects the
invention are equally applicable to other surgical approaches to
the heart, for example, by way of a thoracotomy, or other suitable
access approach.
When the heart is accessed by way of an incision through all or a
portion of the sternum, the opposing blades are adapted to be
inserted into and engage opposite sides of a sternal incision such
that the severed sternum may be forced apart by the action of the
opposing blades to create a working space for operating on the
heart. Typically, the drive mechanism is constructed to spread the
opposing blades apart in a generally parallel fashion, however, the
parting motion may also have a significant curvilinear or angular
component as well.
In one embodiment, the blades may be permanently, integrally, or
inseparably formed with a drive mechanism. Preferably however, at
least a portion of the blades are separable from the drive
mechanism. That is, at least some of the features and functions
associated with the retractor blades are allocated to a structural
component which is separate, separable, or otherwise detachable
from the drive mechanism. The separate component and the drive
mechanism may be manufactured independently and then subsequently
assembled at the factory or, more preferably, at the point of
use.
A retractor construction having a separable component allows the
features and functions of the drive mechanism to remain separate
from the remainder of the retractor assembly and vice versa. This
allows a greatly simplified or depopulated drive mechanism and
allows the separable component to have a much more sophisticated
construction with increased features and functionality.
Accordingly, the simplified drive mechanism, which is typically
required to be made from a hardened steel, is easier and more
economical to manufacture and easier to maintain, clean and
sterilize post surgically. Moreover, the separate component can be
economically made from materials or processes that allow for the
intricate structural features which provide superior
functionality.
In a preferred embodiment, the drive mechanism is constructed to be
resterilized and reused a relatively large number of times, and the
feature-rich separate component is constructed to be disposable,
i.e. discarded after a single surgical use. Thus, the depopulated
drive mechanism, which will be used over and over, can afford to be
constructed to be quite robust with a view to materials and
manufacturing processes that will support the rigors of such
extended surgical service. The separable component, free from the
typical functional requirements of the drive mechanism and the
service requirements of extended surgical re-use, may preferably be
constructed from any number of engineering materials to produce an
economical component having the desired features and which may be
discarded after a single use if desired.
In a preferred embodiment, retractor assembly 10 comprises a drive
12 and first and second platform blades 14 and 16 detachably
connected to drive 12, as illustrated in FIG. 2. Preferably first
platform blade 14 and second platform blade 16 each have one or
more channels or engaging members 18 adapted to engage opposite
sides of an access incision. Activation of drive 12 forces apart
first and second platform blades 14 and 16 thereby causing engaging
members 18 to correspondingly force the incision open to provide
access to the desired surgical site.
In the example of a sternal approach to the heart, engaging members
18 are adapted to engage each side of the incised sternum to
reliably hold and engage the sternum as the sternum is forced open
to expose the thoracic cavity and ultimately the heart. As best
seen in FIG. 9, which illustrates a cross-section of second
platform blade 16, engaging member 18 is generally in the form of a
channel or the like, preferably having a U-shape, curved shape, or
other shape suitable for engaging the incised sternum.
Preferably, engaging member 18 generally has a concave interior
profile 17 for engaging and holding the sternum and a corresponding
convex exterior profile 19 that is relatively smooth so as not to
interfere with other surgical instruments, snag sutures or create
other such difficulties. The engaging members 18 are preferably
constructed to have sufficient strength to withstand the loads
required to spread the sternum yet maintain a suitably low profile
to facilitate easy insertion into the access incision and to
require as little space within the working incision as
possible.
It may be desirable to provide engaging members 18 with features to
reduce trauma to the incision site, increase the traction against
the sides of the incision, or both. A thin pad or layer of non-slip
or atraumatic material (not shown) may be fixed, by way of an
adhesive or other suitable fastening technique, to the interior
profile 17 if desired to reduce slippage and trauma to the severed
sternum or surrounding tissue. Alternatively, the desired features
may be integrally fabricated into engaging members 18. For example,
when platform blades 14 and 16 are injection molded components,
traction features such as raised bumps, ribs, indentations, or the
like can be molded integral into engaging members 18.
Referring to FIGS. 2 6, drive 12 is preferably constructed to force
the platform blades apart in generally opposite directions. Any
type of drive mechanism which provides the desired separating
action of the blades may be suitable. A common, substantially
straight-line parting motion may be provided by a ratchet or rack
arrangement as is generally known in the art. FIG. 3 illustrates a
preferred drive 12 which involves a bar 15, moveable housing 22 and
handle assembly 24 which facilitates movement of moveable housing
22 relative to bar 15. A first end of first blade 14 may be
operably attached to moveable housing 22 and second blade 16 to bar
15.
In a preferred embodiment, bar 15 is a substantially rigid bar
having a stationary or fixed housing 21 assembled thereto and thus
forming bar assembly 23. Fixed housing 21 may be fastened to one
end of bar 15 using one or more mechanical fasteners, an
interference fit, suitable adhesive or bonding compounds, welding,
or any other suitable fastening technique. A first end of second
blade 16 is preferably operably attached to fixed housing 21. As
with moveable housing 22, fixed housing 21 may be of any
configuration which provides for the structural attachment of first
and second platform blades 14 and 16.
Bar 15 preferably includes a number of teeth 13 evenly spaced along
at least a portion of its length. Teeth 13 may have substantially
parallel side portions 11 and may have radiused tops 25. The
exterior edges of teeth 13 may be broken or radiused or have a
chamfer 26 as shown. Handle assembly 24 preferably includes a means
for engaging teeth 13 so as to drive moveable housing 22 relative
to bar 15 to any desired position under load where it remains so
positioned against the load without need for any applied input or
holding force. The means for engaging teeth 13 could be any
suitable gear, ratchet, cog or like mechanism. Bar 15 may also be
adapted and used for receiving an instrument mount, such as those
described in detail below.
In a preferred embodiment, moveable housing 22 is driven using one
or more drive pins which may successively engage teeth 13 in a
cogging manner. Handle assembly 24 includes drive handle 29
connected to first and second cylindrical drive bearings 31 and 32.
Drive bearing 31 preferably has a raised boss 34 extending from one
end to which drive handle 29 may be pivotally connected by way of
pin 33. At the opposite end, drive bearing 31 has first drive pin
27 and second drive pin 28 extending therefrom and terminating at
second drive bearing 32. First and second drive bearings 31 and 32
are spaced apart a distance 35 which is selected to be slightly
greater than the thickness 38 of bar 15 such that a portion of bar
15 may be received between first and second drive bearings 31 and
32. The outside diameters of drive bearings 31 and 32 are selected
so as to fit within guide holes provided in moveable housing 22.
For example, the outside diameter of second drive bearing 32 is
sized to accurately rotate within guide hole 36.
Moveable housing 22 has a bore 37 extending therethrough for
receiving bar 15. Bore 37 generally has a shape corresponding to
the dimensions of the cross-section of the portion of the bar 15
which is to pass through bore 36. With handle assembly 24 properly
positioned within the guide holes provided in moveable housing 22,
it may be assembled to bar 15 by placing the end of bar 15 within
bore 36 and turning handle 29 such that first and second drive pins
27 and 28 become engaged with teeth 13. Once assembled in this
manner, moveable housing 22 may be forced one way or the other
along the length of bar 15 by turning handle 29, and thus drive
bearings 31 and 32, to cause first and second drive pins 27 and 28
to progressively engage teeth 13 along bar 15.
As mentioned above, first and second platform blades 14 and 16 may
be removably assembled to moveable housing 22 and fixed housing 21,
respectively. Platform blades 14 and 16 may be attached in any
suitable fashion including, for example, threaded connections or
other mating features on the platform blades and housings
themselves, ordinary or specialized mechanical fasteners, and cam
or latching mechanisms adapted to secure the platform blades to the
housings. In a preferred embodiment, both moveable housing 22 and
fixed housing 21 are constructed with features that engage, secure
and support first and second platform blades 14 and 16 in an
operable position on drive 12, thus providing an assembled
retractor 10 which is ready for surgical use.
Referring to FIGS. 7 and 8, second platform blade 16 is shown
before and after assembly onto fixed housing 21. Preferably, at
least one of the platform blade 16 or the fixed housing 21 has an
extending protuberance, post or like feature which can be
receivably engaged by the other of the platform blade or housing.
In a preferred embodiment, fixed housing 21 is preferably
constructed to have a latch post 42 adapted to be received within
latch post cavity 45 provided in platform blade 16. Latch post 42
may have a hole, notch, protuberance, or other feature formed
therein which may be engaged in any convenient manner by the
platform blade 16 so that platform blade 16 becomes releasably
locked in place for use.
In a preferred embodiment, latch post 16 has a notch which defines
latch surface 51 and stop surface 52. Platform blade 16 has a latch
member 48, best seen in FIGS. 11A--11A, having a latch body 50
constructed with surfaces 53 and 54 for engaging latch surface 51
and stop surface 52 respectively. Generally transverse to latch
post cavity 45, platform blade 16 has a latch body cavity 56 having
an opening towards upper surface 57 of platform blade 16 for
receiving latch body 50 of latch 48.
Latch 48 is preferably constructed to engage and disengage latch
post 42 by manual rotation of latch knob 49. Latch body 50 includes
cylindrical portion 55 which provides for controlled rotation
within latch body cavity 56. Latch body 50 may be biased towards
the engaged position shown in FIG. 8 by way of any suitable spring
element. Preferably, latch post 42 is provided with an angled tip
43 having a lead-in angle 44 which allows angled tip 43 to slide
against second engaging surface 54 as latch post 42 begins to be
received within latch post cavity 45. As latch post 42 is advanced
further within latch post cavity 45, angled tip 43 causes latch 48
to rotate out of the way about cylindrical portion 55. Near the end
of the advancement of latch post 42 within latch post cavity 45,
the angled tip is advanced beyond latch body 50, and latch 48
(which is biased towards an engaged position) rotates into the
engaged position with second engaging surface 54 biased against
stop surface 52.
With latch 48 and latch body 50 snapped into the engaged position,
any separating force encountered between platform blade 16 and
fixed housing 21 is resisted by action of first engaging surface 53
against latch surface 51. With this configuration, the reaction
force at first engaging surface 53 is advantageously borne by latch
body 50 primarily in compression. Thus, since the loading is
primarily compressive in nature, a high strength material is not
required, and latch 48 can be made from standard engineering
polymers, for example, such as polycarbonate.
When it is desired to remove platform blade 16 from drive 12, the
operator simply turns latch knob 49, causing latch body 50 to be
placed in a disengaged position relative to latch post 42. With
latch 48 disengaged, latch post 42 of fixed housing 21 is free to
be removed from latch post cavity 45 of platform blade 16. As is
apparent from the Figures, a mirror image of the latch assembly
described with reference to platform blade 16 and fixed housing 21
is provided to releasably attach platform blade 14 to moveable
housing 22.
When the retractor assembly is used to gain access to the thoracic
cavity, a good deal of force must be generated to create the
desired opening. For example, a separating force in excess of 100
pounds may be required to be generated at each engaging member 18
to achieve the desired separation of a particular sternum. Such
loads must be carried by the engaging members and transmitted to
drive 12 by way of platform blades 14 and 16. Since platform blades
are preferably made from a suitable engineering polymer (for
example, a glass filled thermoplastic polyurethane resin), it may
be desirable to provide a reinforcing member for each of platform
blades 14 and 16 to ensure that platform blades 14 and 16 will not
break or otherwise rendered inoperable as a result of the loads
encountered during use.
Although the reinforcing members may be a permanent or removable
members within the platform blades themselves, the reinforcing
members are preferably one or more substantially rigid members
extending from each of the fixed housing 21 and the moveable
housing 22. In a preferred embodiment, fixed and moveable housings
21 and 22 have a pin extending therefrom which may be received
within a mating cavity within first and second platform blades 14
and 16. The pin operates to spread the load developed in the
mechanism over a larger internal area within the platform blades 14
and 16 and reduces the effective beam length of unreinforced
platform blade material subjected to the operating loads. The pin
may be straight pin 40' illustrated in FIG. 3. More preferably,
fixed and moveable housings 21 and 22 have tapered pins 40 and
platform blades 14 and 16 have mating tapered cavities 41 for
receiving tapered pins 40. The tapered construction tends to allow
the user to easily align pin 40 with cavity 41 and allows the pins
40 to fit relatively snugly within cavities 41 without significant
binding during insertion that could otherwise occur between
elongate pins and mating cavities which are designed to be very
close fitting.
To provide sufficient load bearing reinforcement, the reinforcing
pins 40 are preferably constructed of a substantially rigid
material, such as steel, and are preferably at least about 0.75
inches long, more preferably at least about 1.125 inches long, and
most preferably between about 1.25 inches to about 2.25 inches
long. In a preferred embodiment, reinforcing pins 40 are made from
AISI 420 stainless steel having a length of about 1.5 inches, an
outside diameter near the housing of about 0.25 inches, and a 2
degree taper angle decreasing towards the free end of the
reinforcing pins 40.
In the preferred embodiments just discussed, platform blade 16 can
be removed from drive 12 with a substantially straight-line
relative motion as indicated by arrow 46. This engagement action
not only provides for simple and intuitive assembly in the
operating room, but also represents a significant safety feature.
Under certain rare circumstances, for example where the drive
through neglect or misuse has become sufficiently damaged during
use that it is unable to close and disengage from the sternum, an
extremely dangerous situation can be created for the patient. In
such exigent circumstances, the configuration described above may
allow the drive to be separated from the in situ platform blades by
releasing the latches and applying a sufficient amount of force in
the direction indicated by arrow 46. Once the drive has been
removed, the detached platform blades may be easily removed from
the patient.
In addition to engaging members 18, detachable platform blades 14
and 16 may incorporate a wide variety of additional features which
enhance the performance of the retractor system. For example, one
or both of platform blades 14 and 16 may have mounting features to
which various instruments used during the procedure can be secured.
In the case where a stabilizer is to be secured to a retractor for
operating on a beating heart, it is critical to minimize or
substantially eliminate the amount of flex and motion attributable
to each component and each connection between each component, from
the component engaging the beating heart to the component which
provides the sternal attachment. To this end, the engaging features
18 which engage the sternum are preferably part of a unitary
platform blade structure which also includes mounting features to
which a stabilizer and other instruments can be mounted. Since the
mounting features and the sternal engaging features are part of the
same component, and therefore there is no mechanical connection
between the two, the stability of an attached instrument against
the forces of a beating heart is greatly improved.
In a preferred embodiment, each of first and second platform blades
14 and 16 include mount features in the form of rails. The rails
allow one or more instruments to be positioned at any desired
location along the operable length of the rail. Preferably, the
rails are oriented in a direction generally perpendicular to the
direction of separation, in this case perpendicular to bar 15. The
rails may be a recessed feature within the body of platform blades
14 and 16. More preferably, the mounting rails extend upwardly from
the body of platform blades 14 and 16.
Referring to FIGS. 7 9, right platform blade 16 has rail 60
extending over at least a portion of the length of platform blade
16. Rail 60 may have a top portion and a bottom portion having a
narrowed region adjacent said top portion. In one embodiment, Rail
60 preferably has a T-shaped cross-section. The T-shaped
configuration has a top portion 61 and a narrowed portion 62, thus
forming mounting tabs 63 and 64 which can be gripped by a number of
appropriately constructed mounts.
The rail may be straight, curved, or a combination of straight and
curved portions. Preferably, at least a portion of the T-shaped
rail is curved in a manner which more closely follows the profile
of the access or incision site (as seen, for example, see FIG. 45).
In a curved rail configuration, instruments extending perpendicular
to a generally central axis 67 of rail 60 will naturally point more
towards a central area between the platform blades 14 and 16, and
thus may require less positional adjustment or manipulation from
their normal, natural or beginning position. In addition, all or a
portion of top portion 61, and more specifically mounting tabs 63
and 64, may be tilted or angled inwardly at an angle 65 as
shown.
Platform blade 16 may be also be provided with a number of suture
holders or stays which can be used to organize or capture various
sutures used in the course of a particular surgery. Since certain
sutures are placed near the beginning of a CABG procedure, such as
pericardial sutures used to position the heart, the placement of
the suture stays in a manner which does not interfere with
subsequent procedures and instruments is an important aspect of the
present invention. Preferably, the suture stays are positioned such
that placing and manipulating the sutures or the various
instruments and instrument mounts employed during surgery can be
accomplished without interfering with each other. Preferably, the
location of the suture stays position the sutures below the level
of the mounting tab 63 and 64 so that a mating instrument mount may
traverse the entire operable length of rail 60 without interfering
with the sutures.
Rail 60 may have one or more grooves, channels, slots or
passageways for receiving a suture. In addition, a suture lock may
be provided in the rail or elsewhere on platform blade 16 so that
the suture may be fixed in place. To accommodate the use of
pericardial sutures, which are often subjected to a significant
amount of tension when used to position the heart, the suture locks
must be adapted to hold the suture material even while under a
significant amount of tensile loading.
In a preferred arrangement for organizing and locking sutures, and
in particular tensioned pericardial sutures, rail 60 has at least
one open slot or passageway formed therein for receiving the free
end portions of a surgically placed suture. The passageways
preferably extend across rail 60 and have a depth which allows the
suture to lay at an elevation sufficiently below mounting tabs 63
and 64 so as not to interfere with an instrument mount sliding
along rail 60. In a preferred embodiment the passageways extend
through at least a portion of narrowed portion 62. Thus, the height
66 of narrowed portion 62 may be selected not only to provide
sufficient space for a desired instrument mount to attach, but also
to ensure that mounting tabs 63 and 64 are sufficiently raised
above the surrounding features of platform blade 16 so that an
instrument mount may be positioned and repositioned along rail 60
without disturbing or disrupting the sutures within the various
passageways.
The passageways may be a single channel for receiving both free
ends of a surgically placed suture or each end may have a separate
channel. In a preferred embodiment, rail 60 has a number of
bifurcated channels 70 at predetermined intervals along its length.
Referring to FIG. 10, bifurcated channel 70 has a single entrance
channel 71 which bifurcates into first and second exit channels 72
and 73. Entrance channel 71 and either one of exit channel 72 or 73
can be used in the same manner as a single channel, with both free
ends 76 and 77 being routed together. Alternatively, both suture
ends may be received within entrance channel 71 and then separated,
one end within exit channel 72 and one end within exit channel
73.
A means for clamping the suture against movement within the suture
channels may be provided on any of entrance channel 71 or exit
channels 72 or 73. Preferably, suture locks are provided on each
exit channel 72 and 73. This allows the surgeon to positively
identify and unlock a desired suture end for further tension
adjustments or other manipulation without unlocking or loosening
the other end of the suture. In addition, placing each suture end
76 and 77 in separate exit channels 72 and 73, each with a
dedicated suture lock, increases the maximum amount of tension that
can be applied to a given suture. Exit channels 72 and 73 may have
recesses 74 and 75, respectively associated therewith for receiving
a suture lock adapted to secure the suture material within the
channels.
A preferred suture lock 80 is illustrated in FIGS. 10 and 12.
Suture lock 80 has a relatively rigid body 83 having a fixed or
pivot end 81 which allows body 83 to pivot within the mating
profile of recess 74 or 75. Pivoting the body 83 about pivot end 81
selectively engages and disengages free end 84 against the wall 78
of exit channel 72 or 73. Alternatively, suture lock 80 may be made
from a more flexible material which, by nature of the elastic
properties of the material, tends to flex about its fixed end
instead of rotate. In a preferred embodiment, fixed or pivot end 81
is substantially cylindrical and recesses 74 and 75 have mating
cylindrical surfaces.
Preferably, the suture lock is angled relative to the wall 78 so
that it is self-locking in one direction. That is, the suture ends
76 or 77 (or both) operate on the free end 84 in such a way as to
force it towards wall 78, and thus against the suture material, in
proportion to the tension, T encountered by suture ends 76 or 77.
Thus, within practical limits, the higher the tension the harder
free end 84 will press or bite against the sutures placed therein.
Conversely, when the suture ends are pulled in the direction
indicated by arrow 79, the suture forces tend to pivot body 83
about pivot 81 such that free end 84 is rotated away from wall 84
allowing the suture to move relatively freely. Preferably, angle 79
between body 83 and wall 78 is nominally about 1 degree to about 30
degrees, more preferably about 5 degrees to about 15 degrees, most
preferably about 10 degrees. Of course, angle 79 is greater as body
83 pivots to accept a suture placed within the suture channel.
Suture lock 80 may be biased towards the locked position,
preferably using a small spring between the suture lock and the
recess 75. In a preferred embodiment, a piece of resilient closed
cell foam 89 is fixed to body 83 to provide the desired biasing
effect. Free end 84 may optionally have a number of teeth or ridges
82 to ensure acceptable traction against the suture material.
Platform blades 14 and 16 may also be provided with soft tissue
retainers to help control and retain the incised tissue and fat in
the immediate vicinity of the blades. Referring to FIGS. 8 and 9,
platform blade 16 includes integrally attached tissue retainer 85.
Tissue retainer 85 is generally at a small distance 88 above the
top of the engaging members 18. Tissue retainer 85 may be made from
a flexible material, such as an elastomer, preferably a
polyurethane elastomer having a durometer in the range of about 45
to about 75 Shore D, more preferably about 55 Shore D. In a
preferred embodiment tissue retainer 85 is injection molded over
the platform blade to form a permanent and inseparable assembly.
Tissue retainer 85 may have a raised outer lip 86 and optionally
having a plurality of slots 87 formed therein to receive and
organize any loose suture ends. Tissue retainer 85 ensures that the
tissue surrounding the access incision does not interfere with the
operation of rail 60 or the suture holders and also provides a
convenient location for attaching surgical drapes of the like
without interfering with the operation of the retractor
assembly.
Although some of the features of the present invention have been
described, for illustration only, with respect to only one of the
platform blades 14 and 16, it should be apparent that both platform
blades 14 and 16 may have similar or identical features. Although
not necessarily so, first platform blade 14 and second platform
blade 16 are preferably substantially mirror images of each
other.
The retractor assembly just described, provides a simplified drive
mechanism for use in conjunction with multi-featured platform
blades. In addition, a number of different platform blades may be
provided for use with a single drive, for instance, tailored to
different sized anatomy or the specifics of different surgical
procedures. Thus, a number of platform blade configurations can be
provided to an operating room and, based upon pertinent prevailing
clinical factors, the proper configuration can be selected, mounted
to drive 12, and used as described above to provide access to a
desired location. Also, with the modular configuration new features
and advancements can be rapidly incorporated into the platform
blades and immediately introduced for use with existing simplified
drives already in place in the operating rooms.
The platform blades themselves represent a surgical platform that
allows instruments to be mounted and stabilized in virtually any
position, even over already placed and secured sutures from the
surgical site accessed by the retractor assembly. Described below
are preferred instrument mounts for use in conjunction with rail 60
to secure a beating heart stabilizer or other instruments such as
heart positioners, saline or medical air blowers, suction devices,
surgical clamps, or vessel occluders.
The Instrument Mount
Referring to FIG. 13, a preferred instrument mount assembly 20 is
shown for mounting an instrument, such as stabilizer assembly 30,
to an instrument mounting rail such as described above with respect
to rail 60 of platform blades 14 and 16. Mount assembly 20 includes
mount base 115 having features to secure mount assembly 20 at a
desired position on an appropriately configured mating rail or
other suitable structure and includes a shaft locking mechanism for
controlling and securing an instrument shaft in a desired position
and orientation.
One important aspect of instrument mount assembly 20 is to provide
the necessary degrees of freedom to allow the instrument to be
easily maneuvered to whatever position may be required by a
particular procedure. As discussed above, an additional aspect with
respect to stabilizing the beating heart is to eliminate or
minimize the flex or motion attributable to the various components
and connections of instrument mount assembly 20. As will be
discussed in more detail below, instrument mount assembly 20 is
uniquely suited for use in stabilizing the beating heart because it
allows sufficient degrees of freedom to easily manipulate the
position of an instrument secured thereto, allows the degrees of
freedom to be frozen or locked in place and, once locked in place,
does not significantly flex or allow movement at any of the
mechanical joints or connections.
Instrument mount assembly 20 provides a number of different
controllable joints that, when in a released condition, allows
motion in one or more predetermined directions or about one or more
degrees of freedom. Although instrument mount assembly 20 may be
used to secure any mounting shaft configuration from straight or
curved substantially rigid shafts to multi-link or segmented ball
and socket type shafts which are relatively flexible until
themselves locked in some manner at each joint along the shaft
length, it is most advantageously constructed to provide the joints
or connections required to position an instrument having a straight
or curved rigid shaft.
In a preferred embodiment, instrument mount assembly 20 has three
releasable joints or connections for controlling the location and
position of the instrument mount assembly and instrument attached
thereto. The mount base may be positioned at a desired location
along an appropriate rail and secured by rail grips 114 and 116.
The position and orientation of the instrument is then determined
by ball joint (or ball and socket joint) 112 between mount base 125
and mount body 110, a rotational joint 157 between mount body 110
and shaft hub assembly 160, and a shaft clamping mechanism within
shaft hub assembly 160 which may allow translation, rotation, or
both of shaft 3 relative to shaft hub assembly 160.
Ball joint 112 is preferably of the ball and socket type having 3
rotational degrees of freedom. Rotational joint 157 allows rotation
of shaft hub assembly 160 about axis 121 as indicated by arrow 113.
The shaft clamping mechanism allows translation of instrument shaft
3 as indicated by arrows 111 as well as rotation about the shaft
itself as indicated by arrow 117. As will be discussed later, a
further ball-joint type connection 201 may be employed between
shaft 3 and the particular end-effector of the instrument.
Instrument mount assembly 20, having the particular joints and
connections identified above, allows all the required areas of the
heart to be conveniently and intuitively accessed by a stabilizer
connected to one end of a substantially rigid shaft. Certainly,
instrument mount assembly 20 could be provided with more or less
degrees of freedom for maneuvering a particular instrument. For
example, to add additional degrees of freedom rotational joint 157
could be replaced with a ball joint and to eliminate degrees of
freedom shaft 3 could be keyed within shaft hub assembly 160 or
ball joint 112 could be replaced with a rotation only joint.
However, it should be noted that excessive degrees of freedom may
tend to make instrument adjustment increasingly difficult and
cumbersome to control while too few degrees of freedom may not
allow the instrument to be easily placed in the desired position or
orientation.
In one embodiment, the various joints and connections are locked
into a desired position by way of a series of knobs. The degrees
freedom provided by ball joint 112 is locked by activation of top
mount knob 120. Both rotational joint 157 and the shaft clamping
mechanism of shaft hub assembly 160 is locked in place by the
activation of side mount knob 118. Base 125 is locked in position
on the rail by activation of mount lever 122. Ball joint 201, as
will be discussed in greater detail below, may be locked in
position by activation of knob 504. This particular sequence of
knobs used to lock down the degrees of freedom associated with
instrument mount assembly 20 tends to allow the user greater
precision in positioning the instrument because degrees of freedom
unnecessary to a particular desired maneuver of the instrument can
be locked down. Most commonly, mount body 110 is placed at a
desired angle or orientation and then fixed in place by locking
ball joint 112, leaving final adjustment to take place using
rotational joint 157 and the shaft movement allowed by the shaft
clamping mechanism of shaft hub assembly 160.
FIGS. 14 20 show in greater detail the various mechanisms which
lock and release the joints or connections associated with
instrument mount assembly 20. FIG. 14 shows an exploded assembly
illustration of instrument mount assembly 20. Instrument mount
assembly 20, and more specifically mount base 125 to which all the
other components are ultimately secured, is preferably constructed
to engage and lock in position on a rail or other suitable
feature.
Preferably, instrument mount assembly 20 has a fixed rail grip 114
adapted to engage mounting tab 64 of rail 60 and a moveable rail
grip 116 adapted to engage mounting tab 63 or rail 60. Rail grips
114 and 116 may generally have hook-like features for gripping
mounting tabs 63 and 64. Rail grip 114 is part of mount base 125
and moveable rail grip 116 is part of articulating hinge member
115, which is pivotally attached to mount base 125 by way of hinge
pins 123 and 124, or other suitable fastener. Articulation of hinge
member 115 and rail grip 116 in clamping manner towards rail grip
114 on mount base 125 effectively clamps mount base 125 onto rail
60 at mounting tabs 63 and 64.
Hinge member 115 may be articulated using any suitable mechanism
capable of pivoting hinge member 115 to a closed position and
holding it there. In a preferred embodiment, best illustrated in
FIGS. 15A 17, hinge member 115 includes follower surface 155 which
may be acted upon by any suitable cam device to drive hinge member
115 about hinge pins 123 and 124, thus urging rail grip 116 towards
rail grip 114.
In a preferred embodiment, hinge member 115 is articulated by
action of cam 145 having cam surface 152 which acts upon follower
surface 155. Cam 145 has a center, C about which cam 145 rotates.
Preferably, cam 145 has bore 127, having its central axis
coincident with center, C. Mount base 125 may have a cam guide 153
around which bore 127 rides for smooth rotation of cam 45 about
center, C. Cam surface 152 has a varying radius, illustrated by
exemplar radial lines R.sub.1, R.sub.2, R.sub.3, R.sub.4, and
R.sub.5. Thus as cam surface 152 is rotated past follower surface
155, from example from R1 to R2, it pushes the follower surface a
greater distance away from center, C, thus causing hinge member 115
to pivot about hinge pins 123 and 124, thus causing rail grip 116
to move closer to rail grip 114.
The varying radius of cam surface 152 may be configured to place
hinge member 115, and thus rail grip 116 in a variety of positions.
A first portion of cam surface 152 may be configured such that
follower surface 155 biased against cam surface 152 is placed in an
position characterized in that rail grip 116 is sufficiently spaced
apart relative to rail grip 114 to allow assembly onto a rail or
other structure. A second portion of cam surface 152 has an
increasing radius such that rotation of cam 145 moves rail grip 116
towards rail grip 114 to an intermediate position. In the
intermediate position, rail grip 116 has been moved close enough to
rail grip 114 so that it becomes captured on a rail but remains
loose enough to slide along the rail. A third portion of cam
surface 152 has an increasing radius such that the rotation of cam
145 moves rail grip 116 further towards rail grip 114 to a
completely locked position wherein relative motion between rail
grips 114, 116 and the rail is essentially no longer possible.
Cam 145 is generally provided with a handle or lever 122 to allow
the user to easily turn cam 145 relative to mount base 125. Cam 145
may be captured onto mount base 125 by operation of retaining hook
150 on cam 145 which rides within exterior groove 151 on mount base
125 on one side, and projection 154 which is engaged below undercut
156 generally opposite to retaining hook 150. Projection 154 also
serves to work against undercut 156 to return hinge member 115 to
the open position as cam 145 is rotated in the opposite (open)
direction. Hinge member 115 preferably has first and second end
stops 158 and 159 between which the motion of projection 154 (and
thus the rotation of cam 145) is limited. Cam 145 may also have a
protective extended portion or cover 163 which shields the area of
groove 151 when assembled over mount base 125.
The assembly of cam 145 and hinge member 115 to mount base 125 is
illustrated in FIGS. 15A and 15B. Cam 145 is placed in position
relative to hinge member 115 with projection 154 in place below
undercut 156. In roughly that position, cam 145 and hinge member
115 are brought over mount base 125 until bore 127 is properly
seated over cam guide 153 and retaining hook 150 is positioned
within groove 151. Pins 123 and 124 are then pressed in place
through holes provided in both mount base 125 and hinge member
115.
Ball joint 112 is generally created between ball 129 provided at
the top of mount base 125 and a socket or mating cavity within
mount body 110 adapted to receive at least a portion of ball 129.
Preferably ball 129 includes a generally spherical portion,
although other curved shapes providing the desired degrees of
freedom may also be suitable. Base post 130 extends vertically
upward through bore 126 of mount base 125 and vertical passageway
128 of mount body 110 until enlarged end portion 130 become biased
against mount base 125. Top mount knob 120 may then be threaded
onto threaded shaft 132 whereby mount base 125 and mount body 110,
with ball 129 received within mount base 125, becomes captured
between top mount knob 120 and enlarged end portion 130. Continued
tightening of top mount knob 120 over threaded shaft 132 forces
ball 129 harder against mount body 110 until the friction between
mating surfaces on ball 129 and mount body 110 become so great as
to effectively resist any relative movement, thus locking ball
joint 112.
The assembly of rotational joint 157 and shaft hub assembly 160 are
shown in FIG. 19. Rotational joint 157 is in the form of a conical
clutch formed between frustoconical surface 138 of clutch member
135 and mating frustoconical surface 139 in mount body 110. Shaft
hub assembly 160 is generally formed as upper and lower shaft locks
136 and 137 are advanced over shaft grip 140 and against instrument
shaft 3 which is positioned between shaft locks 136 and 137 and
outer shaft guide 144. As clutch member 135 is received over the
outside diameter of grip housing 141 of shaft grip 140 tang 164
becomes engaged between upper shaft lock 136 and lower shaft lock
137 thereby preventing relative rotation between clutch member 135
and shaft grip 140.
Side mount knob 118 having threaded shaft 119 extends through mount
body 110 (and consequently through transverse bore 131 in central
portion 167 of base post 130), clutch member 135 and into interior
threads 142 within grip housing 141 of shaft grip 140. Tightening
of side mount knob 118 clamps the assembly together. Thus,
translation and rotation of instrument shaft 3 is prevented as
shaft grip 140 and clutch member 135 are forced together to clamp
or trap instrument shaft 3 between shaft locks 136 and 137 and
outer shaft guide 144. Also, relative rotation between
frustoconical surface 138 of clutch member 135 and mating
frustoconical surface 139 in mount body 110 is prevented as clutch
member 135 is forced against mount body 110. One or both of
frustoconical surface 138 and mating frustoconical surface 139 may
include a number of teeth, ridges, or other features to prevent
rotation when clutch member 135 is forced against mount body
110.
So that the shaft does not become too loose as side mount knob 118
is loosened, a minimum amount of friction between instrument shaft
3 and the clamping surfaces 146 of outer shaft guide 144 is
preferably maintained by providing a biasing load against shaft 3.
Referring to FIG. 20, shaft biasing member 147 is provided within
shaft grip 140 to maintains a biasing load against shaft 3. Shaft
biasing member 147 has a first portion 148 which slides within
counterbore 143 in shaft grip 140. Shaft biasing member 147 may
optionally have a second portion 149 having external dimensions
sized to be received within the inside diameter of compression
spring 133. Compression spring 133 urges end 134 of shaft biasing
member 147 against shaft 3 to force shaft 3 against clamping
surfaces 146. The amount of force is selected to allow instrument
shaft 3 to be easily positioned by hand but would generally not
allow instrument shaft 3 to slide relative to shaft grip 140 under
only its own weight.
Referring to FIG. 21 a preferred instrument mount assembly 20 is
shown fixed to a preferred platform blade 16 having rail 60. As
discussed above, rail 60 has mounting tabs 63 and 64 over which
rail grips 114 and 116 may be secured. Instrument mount assembly 20
can be positioned, maneuvered, and removed virtually anywhere along
rail 60 without disturbing suture 166 locked in place by free end
84 of suture lock 80 below the operating features of instrument
mount assembly 20 within any one of the suture channels provided in
platform blade 16. In addition, rail 60 is placed in close
proximity to engaging member 18 and thus close to the surgical
opening into the patient providing a more direct access to the
heart by an instrument mounted to instrument mount assembly 20.
Since the rail 60 moves in unison with platform blade 16, this
relationship between rail 60 and engaging member 18 is maintained
no matter how much or how little platform blades 14 and 16 have
been spread to create the desired surgical opening. FIGS. 22A 32
illustrate a preferred embodiment of an alternative instrument
mount assembly 220. Preferably, the degrees of freedom available
for maneuvering instrument mount 220 is substantially the same as
that of instrument mount assembly 20. Instrument mount assembly 220
preferably has ball joint 112 between mount base 221 and mount body
222, a rotational joint 157 between mount body 222, and a shaft hub
assembly 227 which allows rotation and translation of an instrument
shaft held between shaft grip 226 and clutch member 226 of shaft
hub assembly 227. Instrument mount assembly 220, however, has a
different mechanism for controlling or locking the various joints
and connections and may also provide a means for releasing and
removing the shaft from the bulk of the remainder of instrument
mount assembly 220.
As just mentioned, the joints and connections themselves are quite
similar between instrument mount assemblies 20 and 220. As before,
ball joint 112 is a ball and socket configuration created between
generally spherical ball 224 provided at the top of mount base 221
and a mating cavity within mount body 222 adapted to receive and
slide against at least a portion of ball 224. Rotational joint 157
may be in the form of a conical clutch formed between frustoconical
surface 243 of clutch member 225 and mating frustoconical surface
244 in mount body 222. An instrument shaft may be clamped in place
within shaft hub assembly 227 by forcing together shaft grip 226
and clutch member 225 thus closing clamp surface 239 of outer shaft
guide 233 towards V-shaped channels 273 on shaft locks 231 and
232.
Instead of locking the joints and connections by way of multiple
knobs as described above with respect to instrument mount assembly
20, instrument mount assembly 220 preferably uses a mechanism which
releases each of ball joint 112, rotational joint 157, and the
shaft clamping mechanism of shaft hub assembly 227 by activation of
a single knob, lever, or other suitable manual interface. Generally
speaking, this is accomplished by utilizing the clamping motion
required to lock one or more of the joints or connections along a
first axis to also lock the remainder of the joints or connections
along remaining axes.
In a preferred embodiment, ball 224 of mount base 221 is locked in
place relative to housing 222 by operation of base post 230. Base
post 230 is assembled through mount base 221 and mount body 222
from the bottom until bottom flange 259 (see FIG. 27) is resisted
against mount base 221. At the top of base post 230 is upper link
portion 256 having pivot hole 257. Cam 235 is attached through
pivot hole 257 at off-center link pivot 238 using a pin or other
suitable fastener and is supported by contact surface 236
associated with mount body 222. Contact surface 236 may be an
integral feature of mount body 222 or may be in a separate mount
body cover 254 which may be selected to have superior wear
characteristics.
With cam 235 in a closed position, as shown in FIG. 24, link pivot
238 is drawn to its maximum distance 251 (or slightly less than the
maximum if the cam is constructed to rotate over center) from
contact surface 236 thus increasing the clamping force between
mount body 222 and ball 224 as the assembly is clamped between cam
235 on the top and bottom flange 259 on the bottom. With cam 235 in
the closed position, ball joint 112 is effectively locked.
By rotating cam 235, by way of handle 237, to an open position as
illustrated in FIG. 25, link pivot 238 is withdrawn to a position
closer to contact surface 236 at a distance 252, thus reducing or
relaxing the clamping forces between mount body 222 and ball 224 of
mount base 221. With cam 235 in the open position, the friction at
ball 224 is reduced to a level that allows the user to easily
manipulate mount body 222 relative to mount base 221.
Mount base 221 may have an insert 253 secured in the bottom thereof
against which bottom flange 259 is caused to seat as upper link
portion 256 is drawn upwards by operation of cam 235. Preferably,
insert 253 includes recess 255 for receiving compression spring 248
captured about base post 230. Compression spring 248 operates
between insert 253, and thus mount base 221, and bottom flange 259
to bias base post 230 towards the unlocked position.
That same motion of base post 230, created by operation of cam 235,
is preferably also used to lock both rotational joint 157 and the
instrument shaft clamping mechanism of shaft hub assembly 227.
Instead of using a threaded shaft to clamp instrument mount
assembly along this axis as did the previous embodiment, instrument
mount assembly 220 preferably utilizes tie pin 240 which is driven
in the direction of arrow 245 causing shaft grip 226 and clutch
member 225 to be forced together to clamp an instrument shaft
placed therein and also causing frustoconical surface 243 of clutch
member 225 to forced against frustoconical surface 244 in mount
body 222.
Tie pin 240 preferably has a generally cylindrical back portion 261
and a front portion which is connected in some manner to shaft grip
226. Preferably, the front portion includes forward extending first
and second flexible prongs 262 and 263. Cylindrical back portion
261 is slidably received within blind hole 272 of release button
242 and is preferably biased in the unlocked direction indicated by
arrow 270 by compression spring 247 positioned within blind hole
272 behind tie pin 240.
Tie pin 240 is preferably driven in the direction of arrow 245 by
the movement of base post 230 which is assembled in the space
between first and second prongs 262 and 263 of tie pin 240.
Preferably, base post 230 has an angled cam or ramp 258 that
engages back wall 269 at the base of first and second prongs 262
and 263. As base post 230 is drawn upwards in the direction of
arrow 271 by cam 235 from the open position of FIG. 25 to the
closed position of FIG. 24, ramp 258 progressively forces back wall
269, and thus tie pin 240, in the direction of indicated by arrow
245.
Tie pin 240, connected at its front end to shaft grip 226, locks an
instrument shaft in place and locks rotational joint 157 in the
same manner as did threaded shaft 119 of instrument mount assembly
20. In sum, tie pin 240 urges shaft grip 226 towards clutch member
225 and mount body 222. The movement of shaft grip 226, having tang
236 engaged between upper and lower shaft locks 231 and 232 of
clutch member 225, closes together in a clamping fashion surfaces
239 on shaft grip 226 and V-shaped channels 273 on clutch member
225. At the same time, shaft grip 226 pushes against clutch member
225 to force frustoconical surface 243 against mating frustoconical
surface 244 with sufficient force to frictionally lock the surfaces
together, thus preventing relative motion therebetween.
The operation of cam 235 has been described as generally moving
between an open position, in which the various joints and
connections of instrument mount assembly 220 are free to be easily
manipulated about their respective degrees of freedom, and a closed
position in which the joints and connections resist any relative
movement and are thus effectively locked in position. However, the
outer cam profile of cam 235 operating against contact surface 236
may be given a profile that has one or more intermediate positions
such that link pivot 238 is placed at an intermediate distance from
contact surface 236. In an intermediate position, the joints and
connections may be in a stiffened or partially locked state which
allows some positional and orientational manipulation with somewhat
higher operator forces that the completely released condition. In
addition, the action of base post 230 may be such that ball joint
112 becomes fully locked before tie pin 240 has completely locked
the remaining degrees of freedom. Thus, cam 235 may have a
completely released position where manipulation about all degrees
of freedom is easily accomplished, an intermediate position in
which only ball joint 112 is fully locked and the remaining degrees
of freedom are unlocked or may be partially locked, and final
closed position in which all degrees of freedom are locked.
Instrument mount assembly 220 may optionally be provided with a
release mechanism allowing shaft grip 226, and thus the instrument
shaft slidably assembled therein, to be released from instrument
mount assembly 220 preferably by activation of release button 242.
This allows instruments associated with instrument mount assembly
220 to be quickly and conveniently removed and replaced or
exchanged.
In a preferred embodiment, first and second prongs 262 and 263 of
tie pin 240 have first and second projections 267 and 268 which
releasably attach tie pin 240 to shaft grip 226. Grip housing 274
of shaft grip 226 is covered with a sleeve having a deep
counterbore 278 and small through hole 279. The depth of
counterbore 278 is longer than the exterior of grip housing 274 so
as to form internal space 290 (see FIG. 25) when assembled. First
and second prongs 262 and 263 can be flexed to position projections
267 and 268 relatively close together for insertion through hole
279 where projections 267 and 268 can then expand apart locking
projections 267 and 268 behind surface 280.
Preferably, projections 267 and 268 have lead-ins 291 and 292 which
urged projections 267 and 268 together as they are advanced through
hole 279 so that shaft grip 226 can simply be aligned with lead-ins
292 and 292 and then snapped into place without any further action.
Alignment of hole 279 is generally quite simply accomplished as the
cylindrical exterior surface 277 of sleeve 260 is slidably received
in a substantially coaxial arrangement within center bore 219 of
clutch member 225. Clutch member 225 may optionally have first and
second flexures 281 and 282 having first and second retaining
features 283 and 284 so that it may be snapped in place and
thereafter retained within mount body 222.
As mentioned above, shaft grip 226 may be released from tie pin
240. To separate tie pin 240, it is necessary to flex first and
second prongs 262 and 263 together so that projections 267 and 268
will again be positioned to fit through hole 280. This may be
accomplished by providing a raised portion 264 having a ramp 266 on
tie pin 240. A sliding member may be advanced up tie pin 240 and
over ramp 266 and raised portion 264 thus flexing prongs 262 and
263 inwards. Preferably, the sliding member is a tip portion 289 of
release button 242. Tie pin 240 is slidably received within blind
hole 272 of release button 242. The internal diameter of blind hole
272 is small enough so that when it is advanced over ramp 266
and/or raised portion 264, prongs 262 and 263 are flexed inwards.
Preferably, the entrance to blind hole 272 has an internal chamfer
288 so that ramp 266 is smoothly engaged as release button 242 is
advanced.
Release button 242 preferably has a generally cylindrical body 285
which is slidably received within mating bore 294 (see FIG. 25) of
mount body 222. Release button 242 is retained in place, and its
sliding travel limited, by release button flange 241 on one end and
spring clip or e-clip 293 assembled within e-clip groove 286 on the
other end. Spring material 246, such as a wave spring washer or
foam material, may be disposed between release button flange 241
and mount body 222 to bias release button 242 outwards. Transverse
to blind hole 272 tip portion 289 also has a clearance slot 287
through which base post 230 passes.
For clarity only, FIGS. 22A 25 have illustrated instrument mount
assembly 220 without hinge member 115 and cam 145 attached.
However, hinge member 115 having rail grip 116 is preferably
pivotally mounted, with cam 145 in place, by way of pins or the
like at hinge mount 228 as described above with reference to
instrument mount assembly 20. As discussed above, cam 145 may be
rotated about cam guide 223 using base lever 122 to secure the
instrument mount to a rail or other suitable structure.
The retractor and instrument mounts described above can be used to
mount and stabilize a great number of instruments for use during
surgery. Preferably, the retractor and instrument mounts are used
to mount a mechanical stabilizer for stabilizing at least a portion
of the beating heart during CABG surgery or the like. Described
below are a number of mechanical stabilizer embodiments that are
particularly beneficial for stabilizing the beating heart,
especially when used in conjunction with the retractors and
instrument mounts described above.
Tissue Stabilizers
Once access to the heart is achieved, and the heart is positioned
if necessary, a means for stabilizing the beating heart is
introduced through the opening created and at least one component
of the stabilizing device of the invention is brought into contact
with the beating heart. The surgeon then applies a stabilizing
force to the beating heart via the stabilizing means which may then
be fixed in place by attachment to a fixed support. When a
retractor or platform is fixed in an open position to expose the
heart, the retractor platform may also provide the stable support
structure to which the stabilizing means is affixed. When the
position of the stabilizing means is fixed by attachment to a
stable support or to the retractor platform, the stabilizing force
is maintained for the duration of the procedure.
The structure of the portion of the stabilizing means which
contacts the heart may include one or more contact members which
exert a stabilizing force on the heart proximate to the site of the
anastomosis. A pair of contact members may be plates or rectangular
members which are placed on either side of the target coronary
artery at the site of the anastomosis and which may have friction
means or tissue spreading or compressing apparatus associated
therewith. The contact members may also be provided by a platform
which may be substantially planar or which may be contoured to fit
conformingly on the surface of the heart. The stabilizing means may
also include a shaft means having several alternative embodiments
to facilitate adjusting the position and orientation of the
instrument. For example, the shaft means may have an adjustable
length and the axis of the shaft means may have at least one ball
joint disposed within its length such that the orientation of the
shaft means relative to another structure such as the contact
members or stable support may be continuously varied. As is
apparent from the description of the several embodiments, each of
the individual embodiments described and illustrated herein has
discrete components and features which may be readily separated
from or combined with the features of any of the other several
embodiments.
Referring to FIGS. 33 37, a preferred stabilizer assembly for
stabilizing the beating heart is comprised of a foot or base
portion 553 attached to a rigid or semi-rigid shaft means or
connecting shaft 3. Base portion 553 typically has one or more
contact members 1 adapted to contact the heart adjacent the site
desired to be stabilized. The contact members 1 may be
substantially planar, may be slightly curved to conform to the
shape of the heart, or may be a non-conforming curve to establish
contact between only a portion of the contact member 1 and the
beating heart. The shape of the contact members may be varied
depending on the clinical assessment by the surgeon, the design of
the other features of the stabilizing means, or the design of other
instruments used to complete the anastomosis. In some embodiments
the contact members 1 may have apertures, openings or attachments
to facilitate connection with sutures or other devices to achieve
the requisite stabilization, occlusion of the target vessel, or
exposure of the target vessel. Examples of suitable base portions
and contact members can be found, for example, in co-pending U.S.
patent application Ser. No. 08/931,158 filed on Sep. 16, 1997,
entitled "SURGICAL INSTRUMENTS AND PROCEDURES FOR STABILIZING THE
BEATING HEART DURING CORONARY ARTERY BYPASS GRAFT SURGERY", the
entirety of which is herein incorporated by reference.
Referring to FIGS. 33 and 34, the proximal end of connecting shaft
3 has handle mechanism 468 assembled thereto which, among other
things, provides the user with a means for locking an end effector
operably attached to the distal end of connecting shaft 3. The
mechanism 468 is rotatably secured to the proximal end of the shaft
means 3 and is formed at a selected angle to the shaft means to
permit a surgeon to swivel the mechanism to a preferred position
where the knob 504 is more readily accessible to allow quickly
locking the shaft means 3 in the orientation selected. In addition,
the angled axis of the knob 504 relative to the shaft means 3
reduces the tendency of the shaft means 3 to rotate about its axis
when a surgeon applies torque to the knob 504 to lock the
associated locking mechanism. The knob 504 is secured to a screw
539 by suitable means such as press fitting, bonding, etc. Right
and left handle covers 540, 541 comprise the handle 503 and provide
the support for the handle mechanism. When assembled, the covers
define generally a cylinder formed with a selected curvature. A
secondary inner molding, generally indicated at 542, includes
various integrally formed annular walls and shoulders for
supporting and containing the knob 504 and screw 539, as well as a
cooperating nut 543, and arcuate wedge 544, a shaft retaining ring
545, the proximal end of the shaft means 3, and a proximal end of
the translatable pushrod 505. The proximal end of the shaft means 3
includes an annular retaining ring slot 546 which secures the
proximal end of the shaft means 3 within suitable annular walls in
the corresponding end of the handle covers 540, 541 when the
retaining ring 545, confined by shoulders in the inner molding 542,
is snapped into the slot 546 and the covers are assembled. The nut
543 is confined by shoulders in the inner molding 542, and the
arcuate wedge 544 is slidably confined by correspondingly arcuate
walls 547 also formed in the inner molding.
As may be seen, rotation of the threaded screw 539 within the
confined threaded nut 543, causes translation of the screw,
pivoting and thus translation of the translatable wedge 544 which
abuts the screw, and translation of the pushrod 505 which abuts the
translatable wedge. As is further described relative to FIGS. 35
37, any tightening or loosening of the screw 539, however slight,
will cause a corresponding translation of the pushrod 505 into or
out of the shaft means 3.
As depicted in the Figures, the shaft means 3 and thus the pushrod
505, are formed with a slight arcuate configuration, which permits
additional degrees of freedom and movement and orientation of the
distal end of the shaft means 3 and thus of the heart contact
member 1. Rotation of the shaft means 3 about the axis of
confinement within the shaft grip 495 or 495a, moves the distal end
of the shaft means 3 through a circular path while changing the
angles through which the contact member 1 can be oriented. This
allows a surgeon to conveniently achieve a wider range of positions
and orientations of the contact member relative to the patient's
heart, while keeping the proximal end of the shaft means 3 and
handle mechanism 468 out of the way as much as possible.
FIGS. 35 37 illustrate an associated mechanism for maneuverably
supporting the various embodiments of the contact member 1 and for
cooperatively assisting in the quick locking of the contact member
by a partial rotation of the knob 504 once the member is
positioned. To this end, the distal end of the shaft means 3 is
provided with exterior threads matching interior threads in a
ball/socket 548. The distal end of ball/socket 548 is provided with
slots 549, whereby the remaining material comprises short extended
tips 550 which, when bent in or inwardly formed, form a socket. A
ball/post 551 includes a ball at one end and a post at the other.
When the mechanism is assembled, the ball/post 551 is inserted into
place within the ball/socket 548 with the ball in the socket and
the post protruding from the ball socket. A mechanism for providing
a preloaded source, such as a compression spring 552, is coupled to
the ball/socket 548 abutting the ball. The spring 552 is urged by
the distal end of the shaft means 3 to exert a preloaded or
constant minimum force against the ball of the ball/post 551. The
post of the ball/post 551 is solidly fixed as by pressing fitting,
welding, etc., to the contact member 1. The distal end of the
pushrod 505 passes through the spring 552 to abut the ball of the
ball/post 551. Thus when the screw 539 is not tightened, the distal
end of the pushrod 505 exerts a slight pressure against the ball,
however the spring 552 maintains a preloaded force against the ball
sufficient to maintain the contact member 1 at any orientation set
by a surgeon. When the screw 539 is tightened, the pushrod 505 is
forced against the ball to prevent any further movement of the
contact member 1. As may be seen, the contact member 1 can be
tilted to assume many orientations since the narrow center of the
post can tilt into any of the four slots 549 in the ball/socket
548. In addition, simultaneous rotation of the curved shaft means 3
provides a surgeon with an even greater variety of orientations of
the contact member relative to a patient's heart.
The contact member 1 includes a preferred configuration which
improves the size of the area of the heart which is visible to a
surgeon while still providing the required suppression of heart
movement necessary to enable the efficient construction of the
anastomosis. More particularly, the pair of spaced-apart contact
members 1 extend from a common base portion 553, which uniquely
first extends back away from the tips of the contact members at the
point of attachment to the post, as shown at reference number 554.
The spaced contact members 1 then curve downward away from the
common base portion 553 and back past the post and away from the
shaft means 3. As may be seen in the FIGS. 35 37, the contact
member 1 of this embodiment uniquely is attached to the post on the
same surface as the surface that bears against the surface of the
beating heart. Since the members 1 separate at the base portion 553
at a point 555 behind the distal end of the shaft means 3, a
surgeon has an unobstructed and thus optimum view of the heart even
below the distal end of the shaft means 3.
The contact members preferably include friction means 556
selectively secured to the bottom surfaces thereof to more securely
engage a beating heart. In addition, the tips of the contact
members are bent upward in the form of "ski tips" to lessen their
impact when the contact members are firmly pressed against a
beating heart to suppress the anastomotic site.
Although screw means 539/504/543 is illustrated herein as a locking
mechanism of the handle mechanism 468, it is to be understood that
other mechanisms may be employed. For example, a cam/lever
mechanism may be attached to a rod which in turn imparts a pivoting
movement or translation to a suitable bellcrank or pivotable
member, which in turn imparts translation to pushrod 505 of the
shaft means 3. Thus, locking mechanisms other than those
specifically described herein may be used.
The basic configuration as just described with reference to base
portion 553 provides the maneuverability necessary to access and
stabilize any desired vessel on the surface of the beating heart.
However, the exact manner and position in which the stabilizer may
be placed relative to the vessel and the surgical techniques
preferred by an individual surgeon may vary significantly.
Accordingly, there is some potential that certain combinations of
stabilizer positioning may interfere somewhat with the preferred
surgical technique of a particular surgeon. The embodiments
illustrated below with respect to FIGS. 38 40B alleviate any such
problems.
One useful variation, as illustrated in FIG. 38, connects
connecting shaft 3 to the base portion of the stabilizer at a
position which is generally offset from the center or off-center.
Base portion 710 is again typically formed of a unitary piece of
sheet material and has a curved back portion in which connecting
shaft 3 is attached to an extension of the same surface which
carries the contacting members, except that the connecting point
718, to which ball/post 551 is attached is positioned away from the
center and therefore away from the space between contact members
712 where the anastomosis would be performed. This configuration
tends to ensure that connecting shaft 3 will not interfere with the
surgical access to the center area of the base portion. Of course,
the connection can be offset from the central region in either
direction.
In addition, base portion 710 illustrates a number of features for
improving the traction and vessel presentation during a CABG
procedure on a beating heart. Contact members 712 of base member
710 have portions 713 having an increased width and which are
preferably substantially flat or slightly curved to conform to the
heart. This configuration provides a larger area for coined regions
715, which represent indentations on the bottom surface for
receiving a traction material, thus providing greater traction
against the surface of the heart.
Further, base portion 710 provides a smaller open space between
contact members 712. In a preferred embodiment, the spacing 716
between contact members 712 is less than about 0.350 inches, more
preferably less than about 0.300 inches, and most preferably about
0.25 inches. This minimized spacing provides stabilization closer
to the vessel and, in some instances, the compressive forces
applied through contact members 712 actually tend to present the
vessel upwards between contact members 712 in a more favorably
pronounced manner. The tip portions 714 of contact members 712 are
angled upwards from the surface of the heart to minimize any
possible trauma to the heart during use.
As just discussed, the base portions (550 or 710) can be
manipulated or oriented relative to the end of the connecting shaft
3 by virtue of the ball and socket joint between base portion 553
and connecting shaft 3. The amount of angular manipulation or
travel available is somewhat limited as ball/post 551 eventually
bottoms out or stops against either the bottom of slots 549 or
extended tips 550. Thus, the contact members have a limited range
of movement relative to connecting shaft 3 based upon the nominal
mounting relationship between the contact members and the
ball/post. Accordingly, for some procedures, it may be desirable to
have a different nominal relationship between the contact members
and the ball/post to shaft connection.
Referring to FIGS. 39 40B, base member 720 illustrates an
alternative orientation of ball/post 551. Instead of being angled
away from the contact members, base member 720 has a back portion
721 which allows ball/socket 551 to be mounted generally parallel
to contact members 722. Ball/post 551 preferably extend towards
contact members 722 as shown, but may also extend the opposite
direction away from the contact members. The connecting point 723
is preferably offset a distance 724 from the central area between
the contact members 722. The connecting point 723 is also off set a
greater distance 726 from the contacting place of contact members
722. In nominal position of base portion 722 relative to ball/post
551, this configuration tends to keep the connecting shaft 3 clear
from the central portion between contact members 722. Furthermore,
relative to connecting shaft 3, contact members 722 can be
maneuvered through a range of motion different from base member 553
due to the initial orientation of ball/post 551. Because the
preferred location of the attachment of the connecting shaft 3 to
the base portion may be different from surgeon to surgeon and from
procedure to procedure, it may be desirable to have the ball/post
moveable to more than one location. In one embodiment shown in FIG.
41, for example, ball/post 562 has threaded end 561 which may be
threaded into any desired threaded receiving hole 563 provided in
stabilizer base 560. Ball post 564 is preferably provided with one
or more flats 564 on the exterior thereof to facilitate tightening
or loosening of the threaded connection. In the embodiment shown,
stabilizer base 560 has threaded receiving holes 563 to provide
center, offset right, and offset left connecting positions.
Referring to FIGS. 42 and 43, ball/post 572 may be captured within
slot 571 formed in stabilizer base 570. Slot 571 preferably has two
or more positions where the ball/post can be positively locked. In
a preferred embodiment, slot 571 preferably has two or more
key-hole openings 573. Key openings 573 are sized to receive first
post portion 577 having an outside diameter which closely matches
the inside dimension of key opening 573. First post portion 577 of
ball/post 572 is released from key hole 573 by pulling ball post in
the direction indicated by arrow 579 until second post portion 578
is positioned within keyhole 573. Second post portion 578 is sized
to have an outside diameter small enough to fit and traverse
through slot 571. Ball/post 572 may then be traversed along the
path defined by slot 571 until the next desired key hole is
reached, which may then be engaged by first post portion 577 to
secure ball/post 572 in position on stabilizer base 570.
First post portion 577 may be kept in engagement with keyholes 573
by any convenient manner. For example, ball/post 572 may be spring
biased in the locked position between upper flange 574 and lower
flange 575, preferably using spring washers 576 as shown. Ball/post
572 may also be locked into operating position within keyholes 573
by using a retaining or locking clip, such as locking clip 580
illustrated with reference to FIGS. 44 and 45. Locking clip 580 has
slot 584 adapted to slide over second post portion 578. Locking
clip 580 includes a thin portion 585, a thick portion 583, a
transition ramp 582 between thin portion 585 and thick portion 583,
and a grip or handle portion 581. With locking clip 580 in the open
position shown in FIG. 44, ball post 572 is free to move upwards in
the direction of arrow 579, thus releasing first post portion 577
from key hole 573. When locking clip 580 is moved in the direction
indicated by arrow 586, the outer thickness of thick portion 583 is
wedged between lower flange 575 and stabilizer base 570, thus
locking ball/post 572 in place within keyhole 573.
Stabilizer base 590 in FIG. 46 has ball/post 592 mounted to an
articulating member which is moveable between two or more
positions. Preferably, ball/post 592 is mounted on first end 594 of
pivoting link 591 which is pivotably attached to stabilizer base
590 at pivot pin 596. Preferably, pivot pin 596 is centrally
located on pivoting link 591. At second end 593 of pivoting link
591, a locking knob 595 may be provided to engage stabilizer base
590. Preferably, locking knob 595 has a threaded shaft or other
such fastening or locking feature which engages mating threaded
holes (typically one positioned under locking knob 595 and one
under ball/post 592) in stabilizer base 590. The ball/post 592 and
locking knob 595 are preferably spaced equal distances from pivot
pin 596 such that when pivoting link 591 is rotated as indicated by
arrow 597, the position of ball/post 592 and locking knob 595 are
reversed.
Another embodiment of a tissue stabilizer having an adjustable
attachment position of the connecting shaft is illustrated in FIGS.
47 50. Stabilizer base assembly 625 includes top member 605 and
stabilizer base 600, having contact members 606 and 607 and notch
or relief 603 under which a vessel may safely pass without being
occluded. At least a portion of stabilizer base 600 has outer
profile 601 which is generally curved or circular at a
predetermined radius. Top member 605 has a mating interior
curvature such that stabilizer base 600 and top member 605
concentrically rotate relative to each other, preferably about a
common center point. Ball/post 602 may be attached at a convenient
position, typically centered, on top member 605. Rotation of top
member 605 relative to stabilizer base 600, as indicated by arrows
620 and 619, thus adjusts the position of ball/post 602 along an
arcuate path relative to contact members 606 and 607.
To facilitate the secure attachment and smooth rotation of top
member 605 relative to stabilizer base 600, top member 605 may be
provided with one or more projections adapted to be received within
guide slots provided in stabilizer base 600. In a preferred
embodiment, top member 605 has side projections or rails 608 and
609 which snap into lower slots or channels 611 and 610 in
stabilizer base 600 as top member 605 is urged into a concentric
position over stabilizer base 600. Rails 608 and 609 slide within
channel 611 and 610 to maintain a secure attachment and controlled
rotation of top member 605 and stabilizer base 600. Top member 605
may optionally have tab 612 adapted to be received within upper
slot 604 on stabilizer base 600. Upper slot 604 may have a
plurality of detents or teeth which form a desired number of
detented positions as tab 612 is rotated around the path of upper
slot 604. In a preferred embodiment, detented position 617 is
formed between tooth 613 and slot end 616 and detented position 618
is formed between tooth 614 and tooth 615. Of course, detented
positions may be created at any desired location using a variety of
alternate constructions. Preferably, the detent action of tab 612
allows the operator to manually select a position of ball/post 602,
but then holds the position of top member 605 relative to
stabilizer base 600 against movement during use to ensure effective
stabilization of a target vessel on the beating heart.
In addition to the critical function of stabilizing the beating
heart, it is also important for the tissue stabilizer to present
the stabilized coronary artery in a manner which allows sutures to
be easily placed around the mouth of the arteriotomy as required to
create the anastomosis. FIGS. 51A 54 illustrate a tissue stabilizer
embodiment involving a base portion having a single contacting
surface for stabilizing a target vessel on the beating heart and a
mechanical bail element to facilitate optimal vessel
presentation.
Referring to FIGS. 51A and 51B stabilizer base 740 is shown
attached to connecting shaft 3 using ball/post 730. Connecting
shaft 3 is shown connected generally to the center of stabilizer
base 740 at approximately a right angle, however, as discussed
above, the ball/post 730 could be connected at any desired offset
or orientation or the position of ball/post 730 could be
adjustable. Stabilizer base 740 preferably has a single contacting
surface 742 which may be flat or curved to at least partially
conform to the surface of the heart. Contacting surface 742 is
sized to provide sufficient contacting area such that sufficient
compressive force can be applied to the beating heart to achieve
effective immobilization or stabilization of a target coronary
artery.
Stablizer base 740 preferably has an extending frame member or bail
745 attached thereto. Bail 745 may be a thin, round or square
cross-sectioned member, and is preferably a stainless steel wire.
Bail 740 has a bail portion 756 which is generally parallel to
stabilizer base 740 and may have relieved sections 747 formed
therein so as not to occlude the vessel during use. Bail portion
756 may have tissue gripping features, such as teeth 755. In an
optional embodiment, bail portion 756 may be provided with rotating
cover or a spiral wound thread (not shown) so that bail portion may
be more easily repositioned, under a stabilizing load, over the
surface of the heart as discussed below.
In a preferred embodiment, bail 745 is moveable relative to
stabilizer base 740. Bail 745 can be moved in or out in the
direction indicated by arrow 750 to cause bail section 756, which
is generally parallel with stabilizer base 740, to compress tissue
towards stabilizer base 740 or stretch tissue away from stabilizer
base 740. Thus, bail 745 can be moved in and out to compress or
stretch the tissue surrounding a coronary artery until the optimum
presentation for performing the anastomosis is achieved. The
generally parallel portion may be vertically offset from contacting
surface 742 by a distance 757 which is typically about 0.050 inches
to about 0.200 inches.
Although bail 745 may be attached in a number of ways, bail 745 is
preferably formed with first and second end portions 748 and 749
having detents or teeth 746. Stabilizer base 740 preferably has
channels 751 and 752 for receiving end portions 749 and 748
respectively. Channels 751 and 752 preferably have internal mating
teeth 753 for engaging teeth 746. End portions 748 and 749 can be
incrementally advanced into channels 752 and 751 as teeth 746
deflect and release from a mated position relative to teeth 753 and
then successively engage the next mated position. Stabilizer base
740 may include cover 754 over channels 751 and 752. So that the
stabilizer can be removed from around a completed anastomosis, at
least one end of bail 745 is detachable from stabilizer base 740.
In a preferred embodiment, stabilizer base 740 is substantially
symmetrical allowing bail 745 to be assembled from either side in a
right or left handed configuration.
Bail 745 is preferably flexible or semi-flexible relative to
stabilizer base 740. As a result of its inherent flexibility, bail
745 applies a predetermined force against the heart that, under
operating conditions, may be generally independent of the
stabilizing force applied to stabilizer base 740 to stabilize the
beating heart. That is, once stabilizer base 740 is forced against
the surface of the heart, the force applied by bail 745 is a
function of its mechanical spring rate relative to stabilizer base
740.
FIGS. 52A and 52B illustrate another single contact stabilizer base
having a bail 762 which is secured at only one end. Stabilizer base
760 may have a housing 765 having a series of internal teeth (not
shown). Bail 762 has a toothed end 766 which is received within
housing 765 to engage with the mating teeth provided therein. As
with the embodiment above, bail 762 has a generally parallel
portion 763 which is moveable relative to stabilizer base 760 in
the direction generally indicated by arrow 767 to stretch or
compress the surrounding tissue for optimum vessel presentation.
Bail 762 may have tab 761 to facilitate grasping by an instrument,
such as for example forceps 761. The free end 764 of bail 762 is
preferably rounded or somewhat bulbous so as to be atraumatic.
Because bail 762 attaches only at one end, the stabilizer can be
easily removed from the completed anastomosis without removing bail
762 from stabilizer base 760.
In another embodiment of the stabilizer, the wire frame member or
bail may have a drive mechanism for moving the bail relative to the
stabilizer base. Referring to FIG. 53 stabilizer base 770 has
housing 771 which is constructed with guide channel 774 having gear
775 mounted for rotation therein. Bail 772 has a toothed end 773
which may be assembled within guide channel 774 such that rotation
of gear 775 causes bail 772 to be moved in and out in the direction
indicated by arrow 43. Gear 775 may be driven by any suitable tool,
for example, gear 775 may have a drive hole 778 for engagement by a
suitable drive tool 771.
Another driven bail stabilizer is shown in FIG. 54. In this
embodiment, stabilizer base 780 has threaded shaft 781 preferably
supported at its end portions by bushings or bearings 783 and 784.
One end of the threaded shaft is connected to a flexible drive 785
through a flexible or universal joint 791. The flexible drive may
be routed up connecting shaft 3. Preferably flexible drive 785 is
secured to connecting shaft 3 by way of a thin polymeric coating.
Bail 782 is connected to threaded collar 787 which cooperates with
threaded shaft 781 to move bail in and out relative to stabilizer
base 780 in the general direction indicated by arrow 790. The screw
and collar drive mechanism is preferably concealed by housing 788
which has only a small slotted opening 786 allowing passage of bail
782.
With each of the flexible bail embodiments described above,
stabilization and vessel presentation are relatively independent.
First, the beating heart is typically stabilized using a
compressive force delivered by way of the single contacting surface
provided by the stabilizer base. The bail may then be manipulated
in or out to obtain the optimum presentation of the vessel for
whatever surgical procedure is underway. For example, one bail
position may be optimal for creating the arteriotomy, another bail
position for insertion of a shunt or like device (should one be
used), another bail position for creating the anastomosis, and so
on. All the while, the stabilization of the beating heart itself
remains optimized by the contacting surface of the stabilizer
base.
The Stabilization System
Preferred embodiments for each of the retractor, the instrument
mount and the tissue stabilizers have been discussed in detail
above. While each component may be utilized separately, superior
access and stabilization can be achieved when the multiple
components are used together for performing a minimally invasive
cardiac surgery, preferably through a sternotomy approach.
Referring to FIG. 55, retractor assembly 900, including drive
mechanism 910 and first and second platform blades 915 and 920, may
be used to spread the sternum, providing access and direct
visualization to the thoracic cavity. Retractor assembly 900 also
allows sutures to be fixed or organized. Stabilizer assembly 800
isolates and provides local immobilization of the target vessel on
the beating heart. Instrument mount assembly 850 facilitates
precise maneuvering of the stabilizer and ensures a stable, motion
free mount at the desired position and orientation.
To begin a typical beating heart CABG procedure using the preferred
stabilization system illustrated in FIG. 55, drive mechanism 910 is
preferably placed in the fully closed position with moveable
housing 925 positioned against or adjacent fixed housing 930. First
platform blade 915 is then assembled to moveable housing 925 and a
second platform blade 920 is assembled to fixed housing 930. After
ensuring that platform blades 915 and 920 are fully and securely
attached to drive mechanism 910, engaging members 935 of platform
blades 915 and 920 are securely seated on the incised sternum
created using standard surgical procedures. Drive handle 940 may
then be rotated clockwise to separate platform blades 915 and 920,
thus creating the desired opening for accessing the beating
heart.
If positioning the heart using sutures to position the heart, the
sutures may be placed through the tissue at the desired location
and secured to platform blades 915 and 920. Sutures 945 may be slid
into suture holder slots 950 to engage the suture. To ensure proper
a proper hold, only one suture strand is preferably engaged within
each suture holder slot 950. Sutures 945 are released from platform
blades 915 and 920 by concurrently pulling back and up on suture
945 while pulling the suture through the suture holder slot
950.
With the heart positioned as desired, instrument mount assembly 850
may be assembled to platform blade 920 (or 915) by hooking
stabilizer mount base 955 onto rail 960 (or 961) at the desired
location and moving the base lever (not visible in this view)
clockwise to the closed position to secure instrument mount
assembly 850 onto rail 960. Mount body 110 may be oriented to the
desired angle by way of ball joint 965 and locked into place by
turning the top mount knob 855 clockwise.
Stabilizer base 810, having contact members 812 and 814, may then
be positioned on the epicardium of the beating heart by gently
lowering connecting shaft 820 using one hand to guide stabilizer
base 810 onto the target area on the heart. Incremental pressure is
applied to stabilizer base 810 situated on the epicardium until the
desired immobilization or stabilization is achieved. Connecting
shaft 820 is secured in the desired position by turning side mount
knob 860 clockwise and stabilizer base 810 is secured in the
desired position relative to connecting shaft 820 by turning the
stabilizer shaft knob 830 clockwise. With the beating heart
stabilized the anastomosis, or other desired procedure, is
completed.
To remove stabilizer base 810, connecting shaft 820 is held with
one hand while side mount knob 860 is loosened with the other hand.
Stabilizer base 810 is then carefully removed from the anastomotic
site. The base lever is moved to the open position to release
instrument mount assembly 850, and stabilizer assembly 800 mounted
thereto, from rail 960 on platform blade 920. When the entire
bypass procedure is completed, drive handle 940 is rotated in the
counter clockwise direction to close drive mechaninsm 910 and
platform blades 915 and 920. Retractor assembly 900 may then be
gently removed from the access incision. To remove platform blades
915 and 920 from moveable housing 925 and fixed housing 930,
respectively, release latches 970 are manually activated and
platform blades 915 and 920 may be pulled generally straight away
from drive mechanism 910. Drive mechanism 910 may then be
sterilized and prepared for use in a subsequent procedure.
While certain embodiments are illustrated in the drawings and have
just been described herein, it will be apparent to those skilled in
the art that many modifications can be made to the embodiments
without departing from the inventive concepts described. For
purposes of illustration only, the principles of the present
invention has been generally described with reference to a coronary
artery bypass procedure, but may readily be applied to other types
surgical procedures not specifically described. Many other uses are
well-known in the art, and the concepts described herein are
equally applicable to those other uses. Further, the different
components of the various exemplar embodiments described above can
be combined in any desirable construction. Accordingly, the
invention is not to be restricted except by the claims which
follow.
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